[maven-release-plugin] prepare release v0.9.0

See:
- https://github.com/raphw/byte-buddy/releases/tag/byte-buddy-1.14.3
- https://github.com/raphw/byte-buddy/compare/byte-buddy-1.14.2...byte-buddy-1.14.3

.github/ISSUE_TEMPLATE/bug_report.md

@@ -42,9 +42,9 @@ Please replace this sentence with log output, if applicable.
 <!-- Please complete the following information: -->
 
 - Operating system (e.g. MacOS Monterey).
-- Java version (i.e. `java --version`, e.g. `17.0.3`).
-- Error Prone version (e.g. `2.15.0`).
-- Error Prone Support version (e.g. `0.3.0`).
+- Java version (i.e. `java --version`, e.g. `17.0.6`).
+- Error Prone version (e.g. `2.18.0`).
+- Error Prone Support version (e.g. `0.8.0`).
 
 ### Additional context
 

.github/workflows/build.yaml

@@ -10,16 +10,16 @@ jobs:
     strategy:
       matrix:
         os: [ ubuntu-22.04 ]
-        jdk: [ 11.0.16, 17.0.4, 19 ]
+        jdk: [ 11.0.18, 17.0.6, 19.0.2 ]
         distribution: [ temurin ]
         experimental: [ false ]
         include:
           - os: macos-12
-            jdk: 17.0.4
+            jdk: 17.0.6
             distribution: temurin
             experimental: false
           - os: windows-2022
-            jdk: 17.0.4
+            jdk: 17.0.6
             distribution: temurin
             experimental: false
           - os: ubuntu-22.04

.github/workflows/pitest-analyze-pr.yml

@@ -18,7 +18,7 @@ jobs:
       - name: Set up JDK
         uses: actions/setup-java@v3.8.0
         with:
-          java-version: 17.0.4
+          java-version: 17.0.6
           distribution: temurin
           cache: maven
       - name: Run Pitest

.github/workflows/pitest-update-pr.yml

@@ -22,7 +22,7 @@ jobs:
       - name: Set up JDK
         uses: actions/setup-java@v3.8.0
         with:
-          java-version: 17.0.4
+          java-version: 17.0.6
           distribution: temurin
           cache: maven
       - name: Download Pitest analysis artifact

documentation-support/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.8.1-SNAPSHOT</version>
+        <version>0.9.0</version>
     </parent>
 
     <artifactId>documentation-support</artifactId>

documentation-support/src/test/java/tech/picnic/errorprone/documentation/BugPatternExtractorTest.java

@@ -14,7 +14,6 @@ import com.google.errorprone.bugpatterns.BugChecker.ClassTreeMatcher;
 import com.google.errorprone.matchers.Description;
 import com.sun.source.tree.ClassTree;
 import java.io.IOException;
-import java.nio.file.Files;
 import java.nio.file.Path;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
@@ -120,7 +119,8 @@ final class BugPatternExtractorTest {
 
   private static void verifyFileMatchesResource(
       Path outputDirectory, String fileName, String resourceName) throws IOException {
-    assertThat(Files.readString(outputDirectory.resolve(fileName)))
+    assertThat(outputDirectory.resolve(fileName))
+        .content(UTF_8)
         .isEqualToIgnoringWhitespace(getResource(resourceName));
   }
 

error-prone-contrib/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.8.1-SNAPSHOT</version>
+        <version>0.9.0</version>
     </parent>
 
     <artifactId>error-prone-contrib</artifactId>
@@ -37,7 +37,7 @@
         <dependency>
             <groupId>${groupId.error-prone}</groupId>
             <artifactId>error_prone_test_helpers</artifactId>
-            <scope>test</scope>
+            <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>${project.groupId}</groupId>

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/DirectReturn.java

@@ -0,0 +1,131 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
+import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.argument;
+import static com.google.errorprone.matchers.Matchers.isSameType;
+import static com.google.errorprone.matchers.Matchers.isVariable;
+import static com.google.errorprone.matchers.Matchers.not;
+import static com.google.errorprone.matchers.Matchers.returnStatement;
+import static com.google.errorprone.matchers.Matchers.staticMethod;
+import static com.google.errorprone.matchers.Matchers.toType;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.BlockTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.AssignmentTree;
+import com.sun.source.tree.BlockTree;
+import com.sun.source.tree.ExpressionStatementTree;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.ReturnTree;
+import com.sun.source.tree.StatementTree;
+import com.sun.source.tree.Tree;
+import com.sun.source.tree.VariableTree;
+import com.sun.tools.javac.code.Symbol;
+import java.util.List;
+import java.util.Optional;
+import tech.picnic.errorprone.bugpatterns.util.MoreASTHelpers;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+
+/**
+ * A {@link BugChecker} that flags unnecessary local variable assignments preceding a return
+ * statement.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Variable assignment is redundant; value can be returned directly",
+    link = BUG_PATTERNS_BASE_URL + "DirectReturn",
+    linkType = CUSTOM,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class DirectReturn extends BugChecker implements BlockTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<StatementTree> VARIABLE_RETURN = returnStatement(isVariable());
+  private static final Matcher<ExpressionTree> MOCKITO_MOCK_OR_SPY_WITH_IMPLICIT_TYPE =
+      allOf(
+          not(toType(MethodInvocationTree.class, argument(0, isSameType(Class.class.getName())))),
+          staticMethod().onClass("org.mockito.Mockito").namedAnyOf("mock", "spy"));
+
+  /** Instantiates a new {@link DirectReturn} instance. */
+  public DirectReturn() {}
+
+  @Override
+  public Description matchBlock(BlockTree tree, VisitorState state) {
+    List<? extends StatementTree> statements = tree.getStatements();
+    if (statements.size() < 2) {
+      return Description.NO_MATCH;
+    }
+
+    StatementTree finalStatement = statements.get(statements.size() - 1);
+    if (!VARIABLE_RETURN.matches(finalStatement, state)) {
+      return Description.NO_MATCH;
+    }
+
+    Symbol variableSymbol = ASTHelpers.getSymbol(((ReturnTree) finalStatement).getExpression());
+    StatementTree precedingStatement = statements.get(statements.size() - 2);
+
+    return tryMatchAssignment(variableSymbol, precedingStatement)
+        .filter(resultExpr -> canInlineToReturnStatement(resultExpr, state))
+        .map(
+            resultExpr ->
+                describeMatch(
+                    precedingStatement,
+                    SuggestedFix.builder()
+                        .replace(
+                            precedingStatement,
+                            String.format("return %s;", SourceCode.treeToString(resultExpr, state)))
+                        .delete(finalStatement)
+                        .build()))
+        .orElse(Description.NO_MATCH);
+  }
+
+  private static Optional<ExpressionTree> tryMatchAssignment(Symbol targetSymbol, Tree tree) {
+    if (tree instanceof ExpressionStatementTree) {
+      return tryMatchAssignment(targetSymbol, ((ExpressionStatementTree) tree).getExpression());
+    }
+
+    if (tree instanceof AssignmentTree) {
+      AssignmentTree assignment = (AssignmentTree) tree;
+      return targetSymbol.equals(ASTHelpers.getSymbol(assignment.getVariable()))
+          ? Optional.of(assignment.getExpression())
+          : Optional.empty();
+    }
+
+    if (tree instanceof VariableTree) {
+      VariableTree declaration = (VariableTree) tree;
+      return declaration.getModifiers().getAnnotations().isEmpty()
+              && targetSymbol.equals(ASTHelpers.getSymbol(declaration))
+          ? Optional.ofNullable(declaration.getInitializer())
+          : Optional.empty();
+    }
+
+    return Optional.empty();
+  }
+
+  /**
+   * Tells whether inlining the given expression to the associated return statement can be done
+   * safely.
+   *
+   * <p>Inlining is generally safe, but in rare cases the operation may have a functional impact.
+   * The sole case considered here is the inlining of a Mockito mock or spy construction without an
+   * explicit type. In such a case the type created depends on context, such as the method's return
+   * type.
+   */
+  private static boolean canInlineToReturnStatement(
+      ExpressionTree expressionTree, VisitorState state) {
+    return !MOCKITO_MOCK_OR_SPY_WITH_IMPLICIT_TYPE.matches(expressionTree, state)
+        || MoreASTHelpers.findMethodExitedOnReturn(state)
+            .filter(m -> MoreASTHelpers.areSameType(expressionTree, m.getReturnType(), state))
+            .isPresent();
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/FluxImplicitBlock.java

@@ -0,0 +1,100 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.common.base.Preconditions.checkState;
+import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.CONCURRENCY;
+import static com.google.errorprone.BugPattern.StandardTags.PERFORMANCE;
+import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.suppliers.Supplier;
+import com.google.errorprone.suppliers.Suppliers;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.tools.javac.code.Type;
+import com.sun.tools.javac.util.Position;
+import java.util.stream.Stream;
+import tech.picnic.errorprone.bugpatterns.util.ThirdPartyLibrary;
+
+/**
+ * A {@link BugChecker} that flags {@link reactor.core.publisher.Flux} operator usages that may
+ * implicitly cause the calling thread to be blocked.
+ *
+ * <p>Note that the methods flagged here are not themselves blocking, but iterating over the
+ * resulting {@link Iterable} or {@link Stream} may be.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Avoid iterating over `Flux`es in an implicitly blocking manner",
+    link = BUG_PATTERNS_BASE_URL + "FluxImplicitBlock",
+    linkType = CUSTOM,
+    severity = WARNING,
+    tags = {CONCURRENCY, PERFORMANCE})
+public final class FluxImplicitBlock extends BugChecker implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<ExpressionTree> FLUX_WITH_IMPLICIT_BLOCK =
+      instanceMethod()
+          .onDescendantOf("reactor.core.publisher.Flux")
+          .namedAnyOf("toIterable", "toStream")
+          .withNoParameters();
+  private static final Supplier<Type> STREAM = Suppliers.typeFromString(Stream.class.getName());
+
+  /** Instantiates a new {@link FluxImplicitBlock} instance. */
+  public FluxImplicitBlock() {}
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    if (!FLUX_WITH_IMPLICIT_BLOCK.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    Description.Builder description =
+        buildDescription(tree).addFix(SuggestedFixes.addSuppressWarnings(state, canonicalName()));
+    if (ThirdPartyLibrary.GUAVA.isIntroductionAllowed(state)) {
+      description.addFix(
+          suggestBlockingElementCollection(
+              tree, "com.google.common.collect.ImmutableList.toImmutableList", state));
+    }
+    description.addFix(
+        suggestBlockingElementCollection(tree, "java.util.stream.Collectors.toList", state));
+
+    return description.build();
+  }
+
+  private static SuggestedFix suggestBlockingElementCollection(
+      MethodInvocationTree tree, String fullyQualifiedCollectorMethod, VisitorState state) {
+    SuggestedFix.Builder importSuggestion = SuggestedFix.builder();
+    String replacementMethodInvocation =
+        SuggestedFixes.qualifyStaticImport(fullyQualifiedCollectorMethod, importSuggestion, state);
+
+    boolean isStream =
+        ASTHelpers.isSubtype(ASTHelpers.getResultType(tree), STREAM.get(state), state);
+    String replacement =
+        String.format(
+            ".collect(%s()).block()%s", replacementMethodInvocation, isStream ? ".stream()" : "");
+    return importSuggestion.merge(replaceMethodInvocation(tree, replacement, state)).build();
+  }
+
+  private static SuggestedFix.Builder replaceMethodInvocation(
+      MethodInvocationTree tree, String replacement, VisitorState state) {
+    int startPosition = state.getEndPosition(ASTHelpers.getReceiver(tree));
+    int endPosition = state.getEndPosition(tree);
+
+    checkState(
+        startPosition != Position.NOPOS && endPosition != Position.NOPOS,
+        "Cannot locate method to be replaced in source code");
+
+    return SuggestedFix.builder().replace(startPosition, endPosition, replacement);
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitValueSource.java

@@ -0,0 +1,307 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
+import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.ALL;
+import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
+import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.anything;
+import static com.google.errorprone.matchers.Matchers.argument;
+import static com.google.errorprone.matchers.Matchers.argumentCount;
+import static com.google.errorprone.matchers.Matchers.classLiteral;
+import static com.google.errorprone.matchers.Matchers.hasArguments;
+import static com.google.errorprone.matchers.Matchers.isPrimitiveOrBoxedPrimitiveType;
+import static com.google.errorprone.matchers.Matchers.isSameType;
+import static com.google.errorprone.matchers.Matchers.methodHasParameters;
+import static com.google.errorprone.matchers.Matchers.staticMethod;
+import static com.google.errorprone.matchers.Matchers.toType;
+import static java.util.function.Predicate.not;
+import static java.util.stream.Collectors.joining;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.MoreJUnitMatchers.HAS_METHOD_SOURCE;
+import static tech.picnic.errorprone.bugpatterns.util.MoreJUnitMatchers.getMethodSourceFactoryNames;
+
+import com.google.auto.service.AutoService;
+import com.google.common.collect.Iterables;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.AnnotationTree;
+import com.sun.source.tree.ClassTree;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.LambdaExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.MethodTree;
+import com.sun.source.tree.NewArrayTree;
+import com.sun.source.tree.ReturnTree;
+import com.sun.source.util.TreeScanner;
+import com.sun.tools.javac.code.Type;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Locale;
+import java.util.Optional;
+import java.util.Set;
+import java.util.function.Predicate;
+import java.util.stream.DoubleStream;
+import java.util.stream.IntStream;
+import java.util.stream.LongStream;
+import java.util.stream.Stream;
+import org.jspecify.annotations.Nullable;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+
+/**
+ * A {@link BugChecker} that flags JUnit tests with a {@link
+ * org.junit.jupiter.params.provider.MethodSource} annotation that can be replaced with an
+ * equivalent {@link org.junit.jupiter.params.provider.ValueSource} annotation.
+ */
+// XXX: Where applicable, also flag `@MethodSource` annotations that reference multiple value
+// factory methods (or that repeat the same value factory method multiple times).
+// XXX: Support inlining of overloaded value factory methods.
+// XXX: Support inlining of value factory methods referenced by multiple `@MethodSource`
+// annotations.
+// XXX: Support value factory return expressions of the form `Stream.of(a, b,
+// c).map(Arguments::argument)`.
+// XXX: Support simplification of test methods that accept additional injected parameters such as
+// `TestInfo`; such parameters should be ignored for the purpose of this check.
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Prefer `@ValueSource` over a `@MethodSource` where possible and reasonable",
+    linkType = CUSTOM,
+    link = BUG_PATTERNS_BASE_URL + "JUnitValueSource",
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class JUnitValueSource extends BugChecker implements MethodTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<ExpressionTree> SUPPORTED_VALUE_FACTORY_VALUES =
+      anyOf(
+          isArrayArgumentValueCandidate(),
+          toType(
+              MethodInvocationTree.class,
+              allOf(
+                  staticMethod()
+                      .onClass("org.junit.jupiter.params.provider.Arguments")
+                      .namedAnyOf("arguments", "of"),
+                  argumentCount(1),
+                  argument(0, isArrayArgumentValueCandidate()))));
+  private static final Matcher<ExpressionTree> ARRAY_OF_SUPPORTED_SINGLE_VALUE_ARGUMENTS =
+      isSingleDimensionArrayCreationWithAllElementsMatching(SUPPORTED_VALUE_FACTORY_VALUES);
+  private static final Matcher<ExpressionTree> ENUMERATION_OF_SUPPORTED_SINGLE_VALUE_ARGUMENTS =
+      toType(
+          MethodInvocationTree.class,
+          allOf(
+              staticMethod()
+                  .onClassAny(
+                      Stream.class.getName(),
+                      IntStream.class.getName(),
+                      LongStream.class.getName(),
+                      DoubleStream.class.getName(),
+                      List.class.getName(),
+                      Set.class.getName(),
+                      "com.google.common.collect.ImmutableList",
+                      "com.google.common.collect.ImmutableSet")
+                  .named("of"),
+              hasArguments(AT_LEAST_ONE, anything()),
+              hasArguments(ALL, SUPPORTED_VALUE_FACTORY_VALUES)));
+  private static final Matcher<MethodTree> IS_UNARY_METHOD_WITH_SUPPORTED_PARAMETER =
+      methodHasParameters(
+          anyOf(
+              isPrimitiveOrBoxedPrimitiveType(),
+              isSameType(String.class),
+              isSameType(state -> state.getSymtab().classType)));
+
+  /** Instantiates a new {@link JUnitValueSource} instance. */
+  public JUnitValueSource() {}
+
+  @Override
+  public Description matchMethod(MethodTree tree, VisitorState state) {
+    if (!IS_UNARY_METHOD_WITH_SUPPORTED_PARAMETER.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    Type parameterType = ASTHelpers.getType(Iterables.getOnlyElement(tree.getParameters()));
+
+    return findMethodSourceAnnotation(tree, state)
+        .flatMap(
+            methodSourceAnnotation ->
+                getSoleLocalFactoryName(methodSourceAnnotation, tree)
+                    .filter(factory -> !hasSiblingReferencingValueFactory(tree, factory, state))
+                    .flatMap(factory -> findSiblingWithName(tree, factory, state))
+                    .flatMap(
+                        factoryMethod ->
+                            tryConstructValueSourceFix(
+                                parameterType, methodSourceAnnotation, factoryMethod, state))
+                    .map(fix -> describeMatch(methodSourceAnnotation, fix)))
+        .orElse(Description.NO_MATCH);
+  }
+
+  /**
+   * Returns the name of the value factory method pointed to by the given {@code @MethodSource}
+   * annotation, if it (a) is the only one and (b) is a method in the same class as the annotated
+   * method.
+   */
+  private static Optional<String> getSoleLocalFactoryName(
+      AnnotationTree methodSourceAnnotation, MethodTree method) {
+    return getElementIfSingleton(getMethodSourceFactoryNames(methodSourceAnnotation, method))
+        .filter(name -> name.indexOf('#') < 0);
+  }
+
+  /**
+   * Tells whether the given method has a sibling method in the same class that depends on the
+   * specified value factory method.
+   */
+  private static boolean hasSiblingReferencingValueFactory(
+      MethodTree tree, String valueFactory, VisitorState state) {
+    return findMatchingSibling(tree, m -> hasValueFactory(m, valueFactory, state), state)
+        .isPresent();
+  }
+
+  private static Optional<MethodTree> findSiblingWithName(
+      MethodTree tree, String methodName, VisitorState state) {
+    return findMatchingSibling(tree, m -> m.getName().contentEquals(methodName), state);
+  }
+
+  private static Optional<MethodTree> findMatchingSibling(
+      MethodTree tree, Predicate<? super MethodTree> predicate, VisitorState state) {
+    return state.findEnclosing(ClassTree.class).getMembers().stream()
+        .filter(MethodTree.class::isInstance)
+        .map(MethodTree.class::cast)
+        .filter(not(tree::equals))
+        .filter(predicate)
+        .findFirst();
+  }
+
+  private static boolean hasValueFactory(
+      MethodTree tree, String valueFactoryMethodName, VisitorState state) {
+    return findMethodSourceAnnotation(tree, state).stream()
+        .anyMatch(
+            annotation ->
+                getMethodSourceFactoryNames(annotation, tree).contains(valueFactoryMethodName));
+  }
+
+  private static Optional<AnnotationTree> findMethodSourceAnnotation(
+      MethodTree tree, VisitorState state) {
+    return HAS_METHOD_SOURCE.multiMatchResult(tree, state).matchingNodes().stream().findFirst();
+  }
+
+  private static Optional<SuggestedFix> tryConstructValueSourceFix(
+      Type parameterType,
+      AnnotationTree methodSourceAnnotation,
+      MethodTree valueFactoryMethod,
+      VisitorState state) {
+    return getSingleReturnExpression(valueFactoryMethod)
+        .flatMap(expression -> tryExtractValueSourceAttributeValue(expression, state))
+        .map(
+            valueSourceAttributeValue ->
+                SuggestedFix.builder()
+                    .addImport("org.junit.jupiter.params.provider.ValueSource")
+                    .replace(
+                        methodSourceAnnotation,
+                        String.format(
+                            "@ValueSource(%s = %s)",
+                            toValueSourceAttributeName(parameterType), valueSourceAttributeValue))
+                    .delete(valueFactoryMethod)
+                    .build());
+  }
+
+  // XXX: This pattern also occurs a few times inside Error Prone; contribute upstream.
+  private static Optional<ExpressionTree> getSingleReturnExpression(MethodTree methodTree) {
+    List<ExpressionTree> returnExpressions = new ArrayList<>();
+    new TreeScanner<@Nullable Void, @Nullable Void>() {
+      @Override
+      public @Nullable Void visitClass(ClassTree node, @Nullable Void unused) {
+        /* Ignore `return` statements inside anonymous/local classes. */
+        return null;
+      }
+
+      @Override
+      public @Nullable Void visitReturn(ReturnTree node, @Nullable Void unused) {
+        returnExpressions.add(node.getExpression());
+        return super.visitReturn(node, unused);
+      }
+
+      @Override
+      public @Nullable Void visitLambdaExpression(
+          LambdaExpressionTree node, @Nullable Void unused) {
+        /* Ignore `return` statements inside lambda expressions. */
+        return null;
+      }
+    }.scan(methodTree, null);
+
+    return getElementIfSingleton(returnExpressions);
+  }
+
+  private static Optional<String> tryExtractValueSourceAttributeValue(
+      ExpressionTree tree, VisitorState state) {
+    List<? extends ExpressionTree> arguments;
+    if (ENUMERATION_OF_SUPPORTED_SINGLE_VALUE_ARGUMENTS.matches(tree, state)) {
+      arguments = ((MethodInvocationTree) tree).getArguments();
+    } else if (ARRAY_OF_SUPPORTED_SINGLE_VALUE_ARGUMENTS.matches(tree, state)) {
+      arguments = ((NewArrayTree) tree).getInitializers();
+    } else {
+      return Optional.empty();
+    }
+
+    /*
+     * Join the values into a comma-separated string, unwrapping `Arguments` factory method
+     * invocations if applicable.
+     */
+    return Optional.of(
+            arguments.stream()
+                .map(
+                    arg ->
+                        arg instanceof MethodInvocationTree
+                            ? Iterables.getOnlyElement(((MethodInvocationTree) arg).getArguments())
+                            : arg)
+                .map(argument -> SourceCode.treeToString(argument, state))
+                .collect(joining(", ")))
+        .map(value -> arguments.size() > 1 ? String.format("{%s}", value) : value);
+  }
+
+  private static String toValueSourceAttributeName(Type type) {
+    String typeString = type.tsym.name.toString();
+
+    switch (typeString) {
+      case "Class":
+        return "classes";
+      case "Character":
+        return "chars";
+      case "Integer":
+        return "ints";
+      default:
+        return typeString.toLowerCase(Locale.ROOT) + 's';
+    }
+  }
+
+  private static <T> Optional<T> getElementIfSingleton(Collection<T> collection) {
+    return Optional.of(collection)
+        .filter(elements -> elements.size() == 1)
+        .map(Iterables::getOnlyElement);
+  }
+
+  private static Matcher<ExpressionTree> isSingleDimensionArrayCreationWithAllElementsMatching(
+      Matcher<? super ExpressionTree> elementMatcher) {
+    return (tree, state) -> {
+      if (!(tree instanceof NewArrayTree)) {
+        return false;
+      }
+
+      NewArrayTree newArray = (NewArrayTree) tree;
+      return newArray.getDimensions().isEmpty()
+          && !newArray.getInitializers().isEmpty()
+          && newArray.getInitializers().stream()
+              .allMatch(element -> elementMatcher.matches(element, state));
+    };
+  }
+
+  private static Matcher<ExpressionTree> isArrayArgumentValueCandidate() {
+    return anyOf(classLiteral(anything()), (tree, state) -> ASTHelpers.constValue(tree) != null);
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/MockitoMockClassReference.java

@@ -0,0 +1,86 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
+import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.argument;
+import static com.google.errorprone.matchers.Matchers.isSameType;
+import static com.google.errorprone.matchers.Matchers.isVariable;
+import static com.google.errorprone.matchers.Matchers.not;
+import static com.google.errorprone.matchers.Matchers.staticMethod;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.Tree;
+import com.sun.source.tree.VariableTree;
+import java.util.List;
+import tech.picnic.errorprone.bugpatterns.util.MoreASTHelpers;
+
+/**
+ * A {@link BugChecker} that flags the use of {@link org.mockito.Mockito#mock(Class)} and {@link
+ * org.mockito.Mockito#spy(Class)} where instead the type to be mocked or spied can be derived from
+ * context.
+ */
+// XXX: This check currently does not flag method invocation arguments. When adding support for
+// this, consider that in some cases the type to be mocked or spied must be specified explicitly so
+// as to disambiguate between method overloads.
+// XXX: This check currently does not flag (implicit or explicit) lambda return expressions.
+// XXX: This check currently does not drop suppressions that become obsolete after the
+// suggested fix is applied; consider adding support for this.
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Don't unnecessarily pass a type to Mockito's `mock(Class)` and `spy(Class)` methods",
+    link = BUG_PATTERNS_BASE_URL + "MockitoMockClassReference",
+    linkType = CUSTOM,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class MockitoMockClassReference extends BugChecker
+    implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<MethodInvocationTree> MOCKITO_MOCK_OR_SPY_WITH_HARDCODED_TYPE =
+      allOf(
+          argument(0, allOf(isSameType(Class.class.getName()), not(isVariable()))),
+          staticMethod().onClass("org.mockito.Mockito").namedAnyOf("mock", "spy"));
+
+  /** Instantiates a new {@link MockitoMockClassReference} instance. */
+  public MockitoMockClassReference() {}
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    if (!MOCKITO_MOCK_OR_SPY_WITH_HARDCODED_TYPE.matches(tree, state)
+        || !isTypeDerivableFromContext(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    List<? extends ExpressionTree> arguments = tree.getArguments();
+    return describeMatch(tree, SuggestedFixes.removeElement(arguments.get(0), arguments, state));
+  }
+
+  private static boolean isTypeDerivableFromContext(MethodInvocationTree tree, VisitorState state) {
+    Tree parent = state.getPath().getParentPath().getLeaf();
+    switch (parent.getKind()) {
+      case VARIABLE:
+        return !ASTHelpers.hasNoExplicitType((VariableTree) parent, state)
+            && MoreASTHelpers.areSameType(tree, parent, state);
+      case ASSIGNMENT:
+        return MoreASTHelpers.areSameType(tree, parent, state);
+      case RETURN:
+        return MoreASTHelpers.findMethodExitedOnReturn(state)
+            .filter(m -> MoreASTHelpers.areSameType(tree, m.getReturnType(), state))
+            .isPresent();
+      default:
+        return false;
+    }
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RedundantStringConversion.java

@@ -7,6 +7,7 @@ import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.Matchers.allOf;
 import static com.google.errorprone.matchers.Matchers.anyMethod;
 import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.anything;
 import static com.google.errorprone.matchers.Matchers.argumentCount;
 import static com.google.errorprone.matchers.Matchers.isNonNullUsingDataflow;
 import static com.google.errorprone.matchers.Matchers.isSameType;
@@ -67,9 +68,7 @@ public final class RedundantStringConversion extends BugChecker
   private static final String EXTRA_STRING_CONVERSION_METHODS_FLAG =
       "RedundantStringConversion:ExtraConversionMethods";
 
-  @SuppressWarnings("UnnecessaryLambda")
-  private static final Matcher<ExpressionTree> ANY_EXPR = (t, s) -> true;
-
+  private static final Matcher<ExpressionTree> ANY_EXPR = anything();
   private static final Matcher<ExpressionTree> LOCALE = isSameType(Locale.class);
   private static final Matcher<ExpressionTree> MARKER = isSubtypeOf("org.slf4j.Marker");
   private static final Matcher<ExpressionTree> STRING = isSameType(String.class);

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RequestMappingAnnotation.java

@@ -74,9 +74,13 @@ public final class RequestMappingAnnotation extends BugChecker implements Method
                   isSameType("java.time.ZoneId"),
                   isSameType("java.util.Locale"),
                   isSameType("java.util.TimeZone"),
+                  isSameType("jakarta.servlet.http.HttpServletRequest"),
+                  isSameType("jakarta.servlet.http.HttpServletResponse"),
                   isSameType("javax.servlet.http.HttpServletRequest"),
                   isSameType("javax.servlet.http.HttpServletResponse"),
                   isSameType("org.springframework.http.HttpMethod"),
+                  isSameType("org.springframework.ui.Model"),
+                  isSameType("org.springframework.validation.BindingResult"),
                   isSameType("org.springframework.web.context.request.NativeWebRequest"),
                   isSameType("org.springframework.web.context.request.WebRequest"),
                   isSameType("org.springframework.web.server.ServerWebExchange"),

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/MoreASTHelpers.java

@@ -5,8 +5,12 @@ import static com.google.common.collect.ImmutableList.toImmutableList;
 
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.VisitorState;
+import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.tree.ClassTree;
+import com.sun.source.tree.LambdaExpressionTree;
 import com.sun.source.tree.MethodTree;
+import com.sun.source.tree.Tree;
+import java.util.Optional;
 
 /**
  * A collection of helper methods for working with the AST.
@@ -46,4 +50,33 @@ public final class MoreASTHelpers {
   public static boolean methodExistsInEnclosingClass(CharSequence methodName, VisitorState state) {
     return !findMethods(methodName, state).isEmpty();
   }
+
+  /**
+   * Returns the {@link MethodTree} from which control flow would exit if there would be a {@code
+   * return} statement at the given {@link VisitorState}'s current {@link VisitorState#getPath()
+   * path}.
+   *
+   * @param state The {@link VisitorState} from which to derive the AST location of interest.
+   * @return A {@link MethodTree}, unless the {@link VisitorState}'s path does not point to an AST
+   *     node located inside a method, or if the (hypothetical) {@code return} statement would exit
+   *     a lambda expression instead.
+   */
+  public static Optional<MethodTree> findMethodExitedOnReturn(VisitorState state) {
+    return Optional.ofNullable(state.findEnclosing(LambdaExpressionTree.class, MethodTree.class))
+        .filter(MethodTree.class::isInstance)
+        .map(MethodTree.class::cast);
+  }
+
+  /**
+   * Tells whether the given trees are of the same type, after type erasure.
+   *
+   * @param treeA The first tree of interest.
+   * @param treeB The second tree of interest.
+   * @param state The {@link VisitorState} describing the context in which the given trees were
+   *     found.
+   * @return Whether the specified trees have the same erased types.
+   */
+  public static boolean areSameType(Tree treeA, Tree treeB, VisitorState state) {
+    return ASTHelpers.isSameType(ASTHelpers.getType(treeA), ASTHelpers.getType(treeB), state);
+  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/MoreJUnitMatchers.java

@@ -1,6 +1,6 @@
 package tech.picnic.errorprone.bugpatterns.util;
 
-import static com.google.common.collect.ImmutableSet.toImmutableSet;
+import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
 import static com.google.errorprone.matchers.Matchers.annotations;
 import static com.google.errorprone.matchers.Matchers.anyOf;
@@ -9,7 +9,7 @@ import static java.util.Objects.requireNonNullElse;
 import static tech.picnic.errorprone.bugpatterns.util.MoreMatchers.hasMetaAnnotation;
 
 import com.google.common.base.Strings;
-import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.ImmutableList;
 import com.google.errorprone.matchers.AnnotationMatcherUtils;
 import com.google.errorprone.matchers.Matcher;
 import com.google.errorprone.matchers.MultiMatcher;
@@ -55,25 +55,59 @@ public final class MoreJUnitMatchers {
    * Returns the names of the JUnit value factory methods specified by the given {@link
    * org.junit.jupiter.params.provider.MethodSource} annotation.
    *
+   * <p>This method differs from {@link #getMethodSourceFactoryDescriptors(AnnotationTree,
+   * MethodTree)} in that it drops any parenthesized method parameter type enumerations. That is,
+   * method descriptors such as {@code factoryMethod()} and {@code factoryMethod(java.lang.String)}
+   * are both simplified to just {@code factoryMethod}. This also means that the returned method
+   * names may not unambiguously reference a single value factory method; in such a case JUnit will
+   * throw an error at runtime.
+   *
    * @param methodSourceAnnotation The annotation from which to extract value factory method names.
-   * @return One or more value factory names.
+   * @param method The method on which the annotation is located.
+   * @return One or more value factory descriptors, in the order defined.
+   * @see #getMethodSourceFactoryDescriptors(AnnotationTree, MethodTree)
    */
-  static ImmutableSet<String> getMethodSourceFactoryNames(
+  // XXX: Drop this method in favour of `#getMethodSourceFactoryDescriptors`. That will require
+  // callers to either explicitly drop information, or perform a more advanced analysis.
+  public static ImmutableList<String> getMethodSourceFactoryNames(
+      AnnotationTree methodSourceAnnotation, MethodTree method) {
+    return getMethodSourceFactoryDescriptors(methodSourceAnnotation, method).stream()
+        .map(
+            descriptor -> {
+              int index = descriptor.indexOf('(');
+              return index < 0 ? descriptor : descriptor.substring(0, index);
+            })
+        .collect(toImmutableList());
+  }
+
+  /**
+   * Returns the descriptors of the JUnit value factory methods specified by the given {@link
+   * org.junit.jupiter.params.provider.MethodSource} annotation.
+   *
+   * @param methodSourceAnnotation The annotation from which to extract value factory method
+   *     descriptors.
+   * @param method The method on which the annotation is located.
+   * @return One or more value factory descriptors, in the order defined.
+   * @see #getMethodSourceFactoryNames(AnnotationTree, MethodTree)
+   */
+  // XXX: Rather than strings, have this method return instances of a value type capable of
+  // resolving the value factory method pointed to.
+  public static ImmutableList<String> getMethodSourceFactoryDescriptors(
       AnnotationTree methodSourceAnnotation, MethodTree method) {
     String methodName = method.getName().toString();
     ExpressionTree value = AnnotationMatcherUtils.getArgument(methodSourceAnnotation, "value");
 
     if (!(value instanceof NewArrayTree)) {
-      return ImmutableSet.of(toMethodSourceFactoryName(value, methodName));
+      return ImmutableList.of(toMethodSourceFactoryDescriptor(value, methodName));
     }
 
     return ((NewArrayTree) value)
         .getInitializers().stream()
-            .map(name -> toMethodSourceFactoryName(name, methodName))
-            .collect(toImmutableSet());
+            .map(name -> toMethodSourceFactoryDescriptor(name, methodName))
+            .collect(toImmutableList());
   }
 
-  private static String toMethodSourceFactoryName(
+  private static String toMethodSourceFactoryDescriptor(
       @Nullable ExpressionTree tree, String annotatedMethodName) {
     return requireNonNullElse(
         Strings.emptyToNull(ASTHelpers.constValue(tree, String.class)), annotatedMethodName);

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/AssertJStringRules.java

@@ -1,11 +1,16 @@
 package tech.picnic.errorprone.refasterrules;
 
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.assertj.core.api.Assertions.assertThat;
 
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import org.assertj.core.api.AbstractAssert;
 import org.assertj.core.api.AbstractStringAssert;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
@@ -89,4 +94,30 @@ final class AssertJStringRules {
       return assertThat(string).doesNotMatch(regex);
     }
   }
+
+  static final class AssertThatPathContent {
+    @BeforeTemplate
+    AbstractStringAssert<?> before(Path path, Charset charset) throws IOException {
+      return assertThat(Files.readString(path, charset));
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractStringAssert<?> after(Path path, Charset charset) {
+      return assertThat(path).content(charset);
+    }
+  }
+
+  static final class AssertThatPathContentUtf8 {
+    @BeforeTemplate
+    AbstractStringAssert<?> before(Path path) throws IOException {
+      return assertThat(Files.readString(path));
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractStringAssert<?> after(Path path) {
+      return assertThat(path).content(UTF_8);
+    }
+  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/BugCheckerRules.java

@@ -0,0 +1,53 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChooser;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;
+import com.google.errorprone.refaster.Refaster;
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+
+/** Refaster rules related to {@link com.google.errorprone.bugpatterns.BugChecker} classes. */
+@OnlineDocumentation
+final class BugCheckerRules {
+  private BugCheckerRules() {}
+
+  /**
+   * Avoid calling {@link BugCheckerRefactoringTestHelper#setFixChooser(FixChooser)} or {@link
+   * BugCheckerRefactoringTestHelper#setImportOrder(String)} with their respective default values.
+   */
+  static final class BugCheckerRefactoringTestHelperIdentity {
+    @BeforeTemplate
+    BugCheckerRefactoringTestHelper before(BugCheckerRefactoringTestHelper helper) {
+      return Refaster.anyOf(
+          helper.setFixChooser(FixChoosers.FIRST), helper.setImportOrder("static-first"));
+    }
+
+    @AfterTemplate
+    BugCheckerRefactoringTestHelper after(BugCheckerRefactoringTestHelper helper) {
+      return helper;
+    }
+  }
+
+  /**
+   * Prefer {@link BugCheckerRefactoringTestHelper.ExpectOutput#expectUnchanged()} over repeating
+   * the input.
+   */
+  // XXX: This rule assumes that the full source code is specified as a single string, e.g. using a
+  // text block. Support for multi-line source code input would require a `BugChecker`
+  // implementation instead.
+  static final class BugCheckerRefactoringTestHelperAddInputLinesExpectUnchanged {
+    @BeforeTemplate
+    BugCheckerRefactoringTestHelper before(
+        BugCheckerRefactoringTestHelper helper, String path, String source) {
+      return helper.addInputLines(path, source).addOutputLines(path, source);
+    }
+
+    @AfterTemplate
+    BugCheckerRefactoringTestHelper after(
+        BugCheckerRefactoringTestHelper helper, String path, String source) {
+      return helper.addInputLines(path, source).expectUnchanged();
+    }
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ImmutableMapRules.java

@@ -6,6 +6,7 @@ import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
 import static java.util.function.Function.identity;
 
+import com.google.common.base.Predicate;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Streams;
@@ -126,8 +127,8 @@ final class ImmutableMapRules {
   }
 
   /**
-   * Don't map a a stream's elements to map entries, only to subsequently collect them into an
-   * {@link ImmutableMap}. The collection can be performed directly.
+   * Don't map a stream's elements to map entries, only to subsequently collect them into an {@link
+   * ImmutableMap}. The collection can be performed directly.
    */
   abstract static class StreamOfMapEntriesToImmutableMap<E, K, V> {
     @Placeholder(allowsIdentity = true)
@@ -315,6 +316,48 @@ final class ImmutableMapRules {
     }
   }
 
+  /**
+   * Prefer creation of an immutable submap using {@link Maps#filterKeys(Map, Predicate)} over more
+   * contrived alternatives.
+   */
+  abstract static class ImmutableMapCopyOfMapsFilterKeys<K, V> {
+    @Placeholder(allowsIdentity = true)
+    abstract boolean keyFilter(@MayOptionallyUse K key);
+
+    @BeforeTemplate
+    ImmutableMap<K, V> before(ImmutableMap<K, V> map) {
+      return map.entrySet().stream()
+          .filter(e -> keyFilter(e.getKey()))
+          .collect(toImmutableMap(Map.Entry::getKey, Map.Entry::getValue));
+    }
+
+    @AfterTemplate
+    ImmutableMap<K, V> after(ImmutableMap<K, V> map) {
+      return ImmutableMap.copyOf(Maps.filterKeys(map, k -> keyFilter(k)));
+    }
+  }
+
+  /**
+   * Prefer creation of an immutable submap using {@link Maps#filterValues(Map, Predicate)} over
+   * more contrived alternatives.
+   */
+  abstract static class ImmutableMapCopyOfMapsFilterValues<K, V> {
+    @Placeholder(allowsIdentity = true)
+    abstract boolean valueFilter(@MayOptionallyUse V value);
+
+    @BeforeTemplate
+    ImmutableMap<K, V> before(ImmutableMap<K, V> map) {
+      return map.entrySet().stream()
+          .filter(e -> valueFilter(e.getValue()))
+          .collect(toImmutableMap(Map.Entry::getKey, Map.Entry::getValue));
+    }
+
+    @AfterTemplate
+    ImmutableMap<K, V> after(ImmutableMap<K, V> map) {
+      return ImmutableMap.copyOf(Maps.filterValues(map, v -> valueFilter(v)));
+    }
+  }
+
   // XXX: Add a rule for this:
   // Maps.transformValues(streamOfEntries.collect(groupBy(fun)), ImmutableMap::copyOf)
   // ->
@@ -323,9 +366,4 @@ final class ImmutableMapRules {
   // map.entrySet().stream().filter(keyPred).forEach(mapBuilder::put)
   // ->
   // mapBuilder.putAll(Maps.filterKeys(map, pred))
-  //
-  // map.entrySet().stream().filter(entry ->
-  // pred(entry.getKey())).collect(toImmutableMap(Map.Entry::getKey, Map.Entry::getValue))
-  // ->
-  // ImmutableMap.copyOf(Maps.filterKeys(map, pred))
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/NullRules.java

@@ -21,11 +21,14 @@ import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 final class NullRules {
   private NullRules() {}
 
-  /** Prefer the {@code ==} operator over {@link Objects#isNull(Object)}. */
+  /**
+   * Prefer the {@code ==} operator (with {@code null} as the second operand) over {@link
+   * Objects#isNull(Object)}.
+   */
   static final class IsNull {
     @BeforeTemplate
     boolean before(@Nullable Object object) {
-      return Objects.isNull(object);
+      return Refaster.anyOf(null == object, Objects.isNull(object));
     }
 
     @AfterTemplate
@@ -34,11 +37,14 @@ final class NullRules {
     }
   }
 
-  /** Prefer the {@code !=} operator over {@link Objects#nonNull(Object)}. */
+  /**
+   * Prefer the {@code !=} operator (with {@code null} as the second operand) over {@link
+   * Objects#nonNull(Object)}.
+   */
   static final class IsNotNull {
     @BeforeTemplate
     boolean before(@Nullable Object object) {
-      return Objects.nonNull(object);
+      return Refaster.anyOf(null != object, Objects.nonNull(object));
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/PreconditionsRules.java

@@ -6,11 +6,13 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.base.Preconditions.checkPositionIndex;
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static java.util.Objects.requireNonNull;
 
 import com.google.common.base.Preconditions;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
+import java.util.Objects;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 
 /** Refaster templates related to statements dealing with {@link Preconditions}. */
@@ -72,8 +74,22 @@ final class PreconditionsRules {
     }
   }
 
-  /** Prefer {@link Preconditions#checkNotNull(Object)} over more verbose alternatives. */
-  static final class CheckNotNull<T> {
+  /** Prefer {@link Objects#requireNonNull(Object)} over non-JDK alternatives. */
+  static final class RequireNonNull<T> {
+    @BeforeTemplate
+    T before(T object) {
+      return checkNotNull(object);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    T after(T object) {
+      return requireNonNull(object);
+    }
+  }
+
+  /** Prefer {@link Objects#requireNonNull(Object)} over more verbose alternatives. */
+  static final class RequireNonNullStatement<T> {
     @BeforeTemplate
     void before(T object) {
       if (object == null) {
@@ -84,12 +100,26 @@ final class PreconditionsRules {
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(T object) {
-      checkNotNull(object);
+      requireNonNull(object);
     }
   }
 
-  /** Prefer {@link Preconditions#checkNotNull(Object, Object)} over more verbose alternatives. */
-  static final class CheckNotNullWithMessage<T> {
+  /** Prefer {@link Objects#requireNonNull(Object, String)} over non-JDK alternatives. */
+  static final class RequireNonNullWithMessage<T> {
+    @BeforeTemplate
+    T before(T object, String message) {
+      return checkNotNull(object, message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    T after(T object, String message) {
+      return requireNonNull(object, message);
+    }
+  }
+
+  /** Prefer {@link Objects#requireNonNull(Object, String)} over more verbose alternatives. */
+  static final class RequireNonNullWithMessageStatement<T> {
     @BeforeTemplate
     void before(T object, String message) {
       if (object == null) {
@@ -100,7 +130,7 @@ final class PreconditionsRules {
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(T object, String message) {
-      checkNotNull(object, message);
+      requireNonNull(object, message);
     }
   }
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ReactorRules.java

@@ -1,14 +1,17 @@
 package tech.picnic.errorprone.refasterrules;
 
+import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.MoreCollectors.toOptional;
 import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.toCollection;
 import static org.assertj.core.api.Assertions.assertThat;
 import static reactor.function.TupleUtils.function;
 
+import com.google.common.collect.ImmutableCollection;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.MoreCollectors;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -17,8 +20,11 @@ import com.google.errorprone.refaster.annotation.NotMatches;
 import com.google.errorprone.refaster.annotation.Placeholder;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.time.Duration;
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Comparator;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Optional;
 import java.util.concurrent.Callable;
 import java.util.function.BiConsumer;
@@ -699,21 +705,21 @@ final class ReactorRules {
     }
   }
 
-  /**
-   * Prefer a collection using {@link MoreCollectors#toOptional()} over more contrived alternatives.
-   */
+  /** Prefer {@link Mono#singleOptional()} over more contrived alternatives. */
   // XXX: Consider creating a plugin that flags/discourages `Mono<Optional<T>>` method return
   // types, just as we discourage nullable `Boolean`s and `Optional`s.
-  static final class MonoCollectToOptional<T> {
+  static final class MonoSingleOptional<T> {
     @BeforeTemplate
     Mono<Optional<T>> before(Mono<T> mono) {
-      return mono.map(Optional::of).defaultIfEmpty(Optional.empty());
+      return Refaster.anyOf(
+          mono.flux().collect(toOptional()),
+          mono.map(Optional::of).defaultIfEmpty(Optional.empty()));
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Mono<Optional<T>> after(Mono<T> mono) {
-      return mono.flux().collect(toOptional());
+      return mono.singleOptional();
     }
   }
 
@@ -806,6 +812,31 @@ final class ReactorRules {
     }
   }
 
+  /**
+   * Prefer {@link Flux#count()} followed by a conversion from {@code long} to {@code int} over
+   * collecting into a list and counting its elements.
+   */
+  static final class FluxCountMapMathToIntExact<T> {
+    @BeforeTemplate
+    Mono<Integer> before(Flux<T> flux) {
+      return Refaster.anyOf(
+          flux.collect(toImmutableList())
+              .map(
+                  Refaster.anyOf(
+                      Collection::size,
+                      List::size,
+                      ImmutableCollection::size,
+                      ImmutableList::size)),
+          flux.collect(toCollection(ArrayList::new))
+              .map(Refaster.anyOf(Collection::size, List::size)));
+    }
+
+    @AfterTemplate
+    Mono<Integer> after(Flux<T> flux) {
+      return flux.count().map(Math::toIntExact);
+    }
+  }
+
   /**
    * Prefer {@link Mono#doOnError(Class, Consumer)} over {@link Mono#doOnError(Predicate, Consumer)}
    * where possible.
@@ -1173,12 +1204,14 @@ final class ReactorRules {
     }
   }
 
-  /** Don't unnecessarily call {@link StepVerifier.Step#expectNext(Object[])}. */
-  static final class StepVerifierStepExpectNextEmpty<T> {
+  /** Don't unnecessarily have {@link StepVerifier.Step} expect no elements. */
+  // XXX: Given an `IsEmpty` matcher that identifies a wide range of guaranteed-empty `Iterable`
+  // expressions, consider also simplifying `step.expectNextSequence(someEmptyIterable)`.
+  static final class StepVerifierStepIdentity<T> {
     @BeforeTemplate
     @SuppressWarnings("unchecked")
     StepVerifier.Step<T> before(StepVerifier.Step<T> step) {
-      return step.expectNext();
+      return Refaster.anyOf(step.expectNext(), step.expectNextCount(0));
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/StreamRules.java

@@ -10,6 +10,7 @@ import com.google.common.collect.Streams;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.Matches;
 import com.google.errorprone.refaster.annotation.MayOptionallyUse;
 import com.google.errorprone.refaster.annotation.Placeholder;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
@@ -19,10 +20,14 @@ import java.util.Objects;
 import java.util.Optional;
 import java.util.function.Function;
 import java.util.function.Predicate;
+import java.util.function.ToDoubleFunction;
+import java.util.function.ToIntFunction;
+import java.util.function.ToLongFunction;
 import java.util.stream.Collector;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+import tech.picnic.errorprone.refaster.matchers.IsLambdaExpressionOrMethodReference;
 
 /** Refaster rules related to expressions dealing with {@link Stream}s. */
 @OnlineDocumentation
@@ -379,4 +384,46 @@ final class StreamRules {
       return stream.allMatch(e -> test(e));
     }
   }
+
+  static final class StreamMapToIntSum<T> {
+    @BeforeTemplate
+    int before(
+        Stream<T> stream,
+        @Matches(IsLambdaExpressionOrMethodReference.class) Function<? super T, Integer> mapper) {
+      return stream.map(mapper).reduce(0, Integer::sum);
+    }
+
+    @AfterTemplate
+    int after(Stream<T> stream, ToIntFunction<T> mapper) {
+      return stream.mapToInt(mapper).sum();
+    }
+  }
+
+  static final class StreamMapToDoubleSum<T> {
+    @BeforeTemplate
+    double before(
+        Stream<T> stream,
+        @Matches(IsLambdaExpressionOrMethodReference.class) Function<? super T, Double> mapper) {
+      return stream.map(mapper).reduce(0.0, Double::sum);
+    }
+
+    @AfterTemplate
+    double after(Stream<T> stream, ToDoubleFunction<T> mapper) {
+      return stream.mapToDouble(mapper).sum();
+    }
+  }
+
+  static final class StreamMapToLongSum<T> {
+    @BeforeTemplate
+    long before(
+        Stream<T> stream,
+        @Matches(IsLambdaExpressionOrMethodReference.class) Function<? super T, Long> mapper) {
+      return stream.map(mapper).reduce(0L, Long::sum);
+    }
+
+    @AfterTemplate
+    long after(Stream<T> stream, ToLongFunction<T> mapper) {
+      return stream.mapToLong(mapper).sum();
+    }
+  }
 }

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/DirectReturnTest.java

@@ -0,0 +1,174 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class DirectReturnTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(DirectReturn.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import static org.mockito.Mockito.mock;",
+            "import static org.mockito.Mockito.spy;",
+            "",
+            "import java.util.function.Supplier;",
+            "",
+            "class A {",
+            "  private String field;",
+            "",
+            "  void emptyMethod() {}",
+            "",
+            "  void voidMethod() {",
+            "    toString();",
+            "    return;",
+            "  }",
+            "",
+            "  String directReturnOfParam(String param) {",
+            "    return param;",
+            "  }",
+            "",
+            "  String assignmentToField() {",
+            "    field = toString();",
+            "    return field;",
+            "  }",
+            "",
+            "  Object redundantAssignmentToParam(String param) {",
+            "    // BUG: Diagnostic contains:",
+            "    param = toString();",
+            "    return param;",
+            "  }",
+            "",
+            "  String redundantMockAssignmentToParam(String param) {",
+            "    // BUG: Diagnostic contains:",
+            "    param = mock();",
+            "    return param;",
+            "  }",
+            "",
+            "  Object redundantMockWithExplicitTypeAssignmentToParam(String param) {",
+            "    // BUG: Diagnostic contains:",
+            "    param = mock(String.class);",
+            "    return param;",
+            "  }",
+            "",
+            "  Object salientMockAssignmentToParam(String param) {",
+            "    param = mock();",
+            "    return param;",
+            "  }",
+            "",
+            "  String redundantAssignmentToLocalVariable() {",
+            "    String variable = null;",
+            "    // BUG: Diagnostic contains:",
+            "    variable = toString();",
+            "    return variable;",
+            "  }",
+            "",
+            "  String unusedAssignmentToLocalVariable(String param) {",
+            "    String variable = null;",
+            "    variable = toString();",
+            "    return param;",
+            "  }",
+            "",
+            "  String redundantVariableDeclaration() {",
+            "    // BUG: Diagnostic contains:",
+            "    String variable = toString();",
+            "    return variable;",
+            "  }",
+            "",
+            "  String redundantSpyVariableDeclaration() {",
+            "    // BUG: Diagnostic contains:",
+            "    String variable = spy();",
+            "    return variable;",
+            "  }",
+            "",
+            "  Object redundantSpyWithExplicitTypeVariableDeclaration() {",
+            "    // BUG: Diagnostic contains:",
+            "    String variable = spy(String.class);",
+            "    return variable;",
+            "  }",
+            "",
+            "  Object salientSpyTypeVariableDeclaration() {",
+            "    String variable = spy(\"name\");",
+            "    return variable;",
+            "  }",
+            "",
+            "  String unusedVariableDeclaration(String param) {",
+            "    String variable = toString();",
+            "    return param;",
+            "  }",
+            "",
+            "  String assignmentToAnnotatedVariable() {",
+            "    @SuppressWarnings(\"HereBeDragons\")",
+            "    String variable = toString();",
+            "    return variable;",
+            "  }",
+            "",
+            "  String complexReturnStatement() {",
+            "    String variable = toString();",
+            "    return variable + toString();",
+            "  }",
+            "",
+            "  String assignmentInsideIfClause() {",
+            "    String variable = null;",
+            "    if (true) {",
+            "      variable = toString();",
+            "    }",
+            "    return variable;",
+            "  }",
+            "",
+            "  String redundantAssignmentInsideElseClause() {",
+            "    String variable = toString();",
+            "    if (true) {",
+            "      return variable;",
+            "    } else {",
+            "      // BUG: Diagnostic contains:",
+            "      variable = \"foo\";",
+            "      return variable;",
+            "    }",
+            "  }",
+            "",
+            "  Supplier<String> redundantAssignmentInsideLambda() {",
+            "    return () -> {",
+            "      // BUG: Diagnostic contains:",
+            "      String variable = toString();",
+            "      return variable;",
+            "    };",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    BugCheckerRefactoringTestHelper.newInstance(DirectReturn.class, getClass())
+        .addInputLines(
+            "A.java",
+            "class A {",
+            "  String m1() {",
+            "    String variable = null;",
+            "    variable = toString();",
+            "    return variable;",
+            "  }",
+            "",
+            "  String m2() {",
+            "    String variable = toString();",
+            "    return variable;",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "class A {",
+            "  String m1() {",
+            "    String variable = null;",
+            "    return toString();",
+            "  }",
+            "",
+            "  String m2() {",
+            "    return toString();",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/FluxFlatMapUsageTest.java

@@ -67,7 +67,6 @@ final class FluxFlatMapUsageTest {
   @Test
   void replacementFirstSuggestedFix() {
     BugCheckerRefactoringTestHelper.newInstance(FluxFlatMapUsage.class, getClass())
-        .setFixChooser(FixChoosers.FIRST)
         .addInputLines(
             "A.java",
             "import reactor.core.publisher.Flux;",

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/FluxImplicitBlockTest.java

@@ -0,0 +1,182 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.common.base.Predicates.and;
+import static com.google.common.base.Predicates.containsPattern;
+import static com.google.common.base.Predicates.not;
+import static com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers.SECOND;
+import static com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers.THIRD;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+import org.reactivestreams.Publisher;
+import reactor.core.CorePublisher;
+import reactor.core.publisher.Flux;
+
+final class FluxImplicitBlockTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(FluxImplicitBlock.class, getClass())
+        .expectErrorMessage(
+            "X",
+            and(
+                containsPattern("SuppressWarnings"),
+                containsPattern("toImmutableList"),
+                containsPattern("toList")))
+        .addSourceLines(
+            "A.java",
+            "import com.google.common.collect.ImmutableList;",
+            "import java.util.stream.Stream;",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    // BUG: Diagnostic matches: X",
+            "    Flux.just(1).toIterable();",
+            "    // BUG: Diagnostic matches: X",
+            "    Flux.just(2).toStream();",
+            "    // BUG: Diagnostic matches: X",
+            "    long count = Flux.just(3).toStream().count();",
+            "",
+            "    Flux.just(4).toIterable(1);",
+            "    Flux.just(5).toIterable(2, null);",
+            "    Flux.just(6).toStream(3);",
+            "    new Foo().toIterable();",
+            "    new Foo().toStream();",
+            "  }",
+            "",
+            "  class Foo<T> {",
+            "    Iterable<T> toIterable() {",
+            "      return ImmutableList.of();",
+            "    }",
+            "",
+            "    Stream<T> toStream() {",
+            "      return Stream.empty();",
+            "    }",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void identificationWithoutGuavaOnClasspath() {
+    CompilationTestHelper.newInstance(FluxImplicitBlock.class, getClass())
+        .withClasspath(CorePublisher.class, Flux.class, Publisher.class)
+        .expectErrorMessage("X", not(containsPattern("toImmutableList")))
+        .addSourceLines(
+            "A.java",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    // BUG: Diagnostic matches: X",
+            "    Flux.just(1).toIterable();",
+            "    // BUG: Diagnostic matches: X",
+            "    Flux.just(2).toStream();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacementFirstSuggestedFix() {
+    BugCheckerRefactoringTestHelper.newInstance(FluxImplicitBlock.class, getClass())
+        .addInputLines(
+            "A.java",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).toIterable();",
+            "    Flux.just(2).toStream();",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  @SuppressWarnings(\"FluxImplicitBlock\")",
+            "  void m() {",
+            "    Flux.just(1).toIterable();",
+            "    Flux.just(2).toStream();",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+
+  @Test
+  void replacementSecondSuggestedFix() {
+    BugCheckerRefactoringTestHelper.newInstance(FluxImplicitBlock.class, getClass())
+        .setFixChooser(SECOND)
+        .addInputLines(
+            "A.java",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).toIterable();",
+            "    Flux.just(2).toStream();",
+            "    Flux.just(3).toIterable().iterator();",
+            "    Flux.just(4).toStream().count();",
+            "    Flux.just(5) /* a */./* b */ toIterable /* c */(/* d */ ) /* e */;",
+            "    Flux.just(6) /* a */./* b */ toStream /* c */(/* d */ ) /* e */;",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static com.google.common.collect.ImmutableList.toImmutableList;",
+            "",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(toImmutableList()).block();",
+            "    Flux.just(2).collect(toImmutableList()).block().stream();",
+            "    Flux.just(3).collect(toImmutableList()).block().iterator();",
+            "    Flux.just(4).collect(toImmutableList()).block().stream().count();",
+            "    Flux.just(5).collect(toImmutableList()).block() /* e */;",
+            "    Flux.just(6).collect(toImmutableList()).block().stream() /* e */;",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+
+  @Test
+  void replacementThirdSuggestedFix() {
+    BugCheckerRefactoringTestHelper.newInstance(FluxImplicitBlock.class, getClass())
+        .setFixChooser(THIRD)
+        .addInputLines(
+            "A.java",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).toIterable();",
+            "    Flux.just(2).toStream();",
+            "    Flux.just(3).toIterable().iterator();",
+            "    Flux.just(4).toStream().count();",
+            "    Flux.just(5) /* a */./* b */ toIterable /* c */(/* d */ ) /* e */;",
+            "    Flux.just(6) /* a */./* b */ toStream /* c */(/* d */ ) /* e */;",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static java.util.stream.Collectors.toList;",
+            "",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(toList()).block();",
+            "    Flux.just(2).collect(toList()).block().stream();",
+            "    Flux.just(3).collect(toList()).block().iterator();",
+            "    Flux.just(4).collect(toList()).block().stream().count();",
+            "    Flux.just(5).collect(toList()).block() /* e */;",
+            "    Flux.just(6).collect(toList()).block().stream() /* e */;",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/IdentityConversionTest.java

@@ -180,7 +180,6 @@ final class IdentityConversionTest {
   @Test
   void replacementFirstSuggestedFix() {
     BugCheckerRefactoringTestHelper.newInstance(IdentityConversion.class, getClass())
-        .setFixChooser(FixChoosers.FIRST)
         .addInputLines(
             "A.java",
             "import static com.google.errorprone.matchers.Matchers.staticMethod;",

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/JUnitValueSourceTest.java

@@ -0,0 +1,496 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class JUnitValueSourceTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(JUnitValueSource.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import static org.junit.jupiter.params.provider.Arguments.arguments;",
+            "",
+            "import java.util.Optional;",
+            "import java.util.stream.Stream;",
+            "import org.junit.jupiter.params.ParameterizedTest;",
+            "import org.junit.jupiter.params.provider.Arguments;",
+            "import org.junit.jupiter.params.provider.MethodSource;",
+            "",
+            "class A {",
+            "  private static Stream<Arguments> identificationTestCases() {",
+            "    return Stream.of(arguments(1), Arguments.of(2));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  // BUG: Diagnostic contains:",
+            "  @MethodSource(\"identificationTestCases\")",
+            "  void identification(int foo) {}",
+            "",
+            "  private static int[] identificationWithParensTestCases() {",
+            "    return new int[] {1, 2};",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  // BUG: Diagnostic contains:",
+            "  @MethodSource(\"identificationWithParensTestCases()\")",
+            "  void identificationWithParens(int foo) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"valueFactoryMissingTestCases\")",
+            "  void valueFactoryMissing(int foo) {}",
+            "",
+            "  private static Stream<Arguments> multipleUsagesTestCases() {",
+            "    return Stream.of(arguments(1), Arguments.of(2));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"multipleUsagesTestCases\")",
+            "  void multipleUsages1(int foo) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"multipleUsagesTestCases()\")",
+            "  void multipleUsages2(int bar) {}",
+            "",
+            "  private static Stream<Arguments> valueFactoryRepeatedTestCases() {",
+            "    return Stream.of(arguments(1), arguments(2));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource({\"valueFactoryRepeatedTestCases\", \"valueFactoryRepeatedTestCases\"})",
+            "  void valueFactoryRepeated(int foo) {}",
+            "",
+            "  private static Stream<Arguments> multipleParametersTestCases() {",
+            "    return Stream.of(arguments(1, 2), arguments(3, 4));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"multipleParametersTestCases\")",
+            "  void multipleParameters(int first, int second) {}",
+            "",
+            "  private static int[] arrayWithoutInitializersTestCases() {",
+            "    return new int[1];",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"arrayWithoutInitializersTestCases\")",
+            "  void arrayWithoutInitializers(int foo) {}",
+            "",
+            "  private static Stream<Arguments> runtimeValueTestCases() {",
+            "    int second = 2;",
+            "    return Stream.of(arguments(1), arguments(second));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"runtimeValueTestCases\")",
+            "  void runtimeValue(int foo) {}",
+            "",
+            "  private static Stream<Arguments> streamChainTestCases() {",
+            "    return Stream.of(1, 2).map(Arguments::arguments);",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"streamChainTestCases\")",
+            "  void streamChain(int number) {}",
+            "",
+            "  private static Stream<Arguments> multipleReturnsTestCases() {",
+            "    if (true) {",
+            "      return Stream.of(arguments(1), arguments(2));",
+            "    } else {",
+            "      return Stream.of(arguments(3), arguments(4));",
+            "    }",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"multipleReturnsTestCases\")",
+            "  void multipleReturns(int number) {}",
+            "",
+            "  private static Stream<Arguments> multipleFactoriesFooTestCases() {",
+            "    return Stream.of(arguments(1));",
+            "  }",
+            "",
+            "  private static Stream<Arguments> multipleFactoriesBarTestCases() {",
+            "    return Stream.of(arguments(1));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource({\"multipleFactoriesFooTestCases\", \"multipleFactoriesBarTestCases\"})",
+            "  void multipleFactories(int i) {}",
+            "",
+            "  private static Stream<Arguments> extraArgsTestCases() {",
+            "    return Stream.of(arguments(1), arguments(1, 2));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"extraArgsTestCases\")",
+            "  void extraArgs(int... i) {}",
+            "",
+            "  private static Stream<Arguments> localClassTestCases() {",
+            "    class Foo {",
+            "      Stream<Arguments> foo() {",
+            "        return Stream.of(arguments(1), arguments(2));",
+            "      }",
+            "    }",
+            "    return Stream.of(arguments(1), arguments(2));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  // BUG: Diagnostic contains:",
+            "  @MethodSource(\"localClassTestCases\")",
+            "  void localClass(int i) {}",
+            "",
+            "  private static Stream<Arguments> lambdaReturnTestCases() {",
+            "    int foo =",
+            "        Optional.of(10)",
+            "            .map(",
+            "                i -> {",
+            "                  return i / 2;",
+            "                })",
+            "            .orElse(0);",
+            "    return Stream.of(arguments(1), arguments(1));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  // BUG: Diagnostic contains:",
+            "  @MethodSource(\"lambdaReturnTestCases\")",
+            "  void lambdaReturn(int i) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"tech.picnic.errorprone.Foo#fooTestCases\")",
+            "  void staticMethodReference(int foo) {}",
+            "",
+            "  private static Stream<Arguments> valueFactoryWithArgumentTestCases(int amount) {",
+            "    return Stream.of(arguments(1), arguments(2));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  // BUG: Diagnostic contains:",
+            "  @MethodSource(\"valueFactoryWithArgumentTestCases\")",
+            "  void valueFactoryWithArgument(int foo) {}",
+            "",
+            "  private static Arguments[] emptyArrayValueFactoryTestCases() {",
+            "    return new Arguments[] {};",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"emptyArrayValueFactoryTestCases\")",
+            "  void emptyArrayValueFactory(int foo) {}",
+            "",
+            "  private static Stream<Arguments> emptyStreamValueFactoryTestCases() {",
+            "    return Stream.of();",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"emptyStreamValueFactoryTestCases\")",
+            "  void emptyStreamValueFactory(int foo) {}",
+            "",
+            "  private static Arguments[] invalidValueFactoryArgumentsTestCases() {",
+            "    return new Arguments[] {arguments(1), arguments(new Object() {})};",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"invalidValueFactoryArgumentsTestCases\")",
+            "  void invalidValueFactoryArguments(int foo) {}",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    BugCheckerRefactoringTestHelper.newInstance(JUnitValueSource.class, getClass())
+        .addInputLines(
+            "A.java",
+            "import static org.junit.jupiter.params.provider.Arguments.arguments;",
+            "",
+            "import com.google.common.collect.ImmutableList;",
+            "import com.google.common.collect.ImmutableSet;",
+            "import java.util.List;",
+            "import java.util.Set;",
+            "import java.util.stream.DoubleStream;",
+            "import java.util.stream.IntStream;",
+            "import java.util.stream.LongStream;",
+            "import java.util.stream.Stream;",
+            "import org.junit.jupiter.params.ParameterizedTest;",
+            "import org.junit.jupiter.params.provider.Arguments;",
+            "import org.junit.jupiter.params.provider.MethodSource;",
+            "",
+            "class A {",
+            "  private static final boolean CONST_BOOLEAN = false;",
+            "  private static final byte CONST_BYTE = 42;",
+            "  private static final char CONST_CHARACTER = 'a';",
+            "  private static final short CONST_SHORT = 42;",
+            "  private static final int CONST_INTEGER = 42;",
+            "  private static final long CONST_LONG = 42;",
+            "  private static final float CONST_FLOAT = 42;",
+            "  private static final double CONST_DOUBLE = 42;",
+            "  private static final String CONST_STRING = \"foo\";",
+            "",
+            "  private static Stream<Arguments> streamOfBooleanArguments() {",
+            "    return Stream.of(arguments(false), arguments(true), arguments(CONST_BOOLEAN));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"streamOfBooleanArguments\")",
+            "  void primitiveBoolean(boolean b) {}",
+            "",
+            "  private static Stream<Object> streamOfBooleansAndBooleanArguments() {",
+            "    return Stream.of(false, arguments(true), CONST_BOOLEAN);",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"streamOfBooleansAndBooleanArguments\")",
+            "  void boxedBoolean(Boolean b) {}",
+            "",
+            "  private static List<Arguments> listOfByteArguments() {",
+            "    return List.of(arguments((byte) 0), arguments((byte) 1), arguments(CONST_BYTE));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"listOfByteArguments\")",
+            "  void primitiveByte(byte b) {}",
+            "",
+            "  private static List<Object> listOfBytesAndByteArguments() {",
+            "    return List.of((byte) 0, arguments((byte) 1), CONST_BYTE);",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"listOfBytesAndByteArguments\")",
+            "  void boxedByte(Byte b) {}",
+            "",
+            "  private static Set<Arguments> setOfCharacterArguments() {",
+            "    return Set.of(arguments((char) 0), arguments((char) 1), arguments(CONST_CHARACTER));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"setOfCharacterArguments\")",
+            "  void primitiveCharacter(char c) {}",
+            "",
+            "  private static Set<Object> setOfCharactersAndCharacterArguments() {",
+            "    return Set.of((char) 0, arguments((char) 1), CONST_CHARACTER);",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"setOfCharactersAndCharacterArguments\")",
+            "  void boxedCharacter(Character c) {}",
+            "",
+            "  private static Arguments[] arrayOfShortArguments() {",
+            "    return new Arguments[] {arguments((short) 0), arguments((short) 1), arguments(CONST_SHORT)};",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"arrayOfShortArguments\")",
+            "  void primitiveShort(short s) {}",
+            "",
+            "  private static Object[] arrayOfShortsAndShortArguments() {",
+            "    return new Object[] {(short) 0, arguments((short) 1), CONST_SHORT};",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"arrayOfShortsAndShortArguments\")",
+            "  void boxedShort(Short s) {}",
+            "",
+            "  private static IntStream intStream() {",
+            "    return IntStream.of(0, 1, CONST_INTEGER);",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"intStream\")",
+            "  void primitiveInteger(int i) {}",
+            "",
+            "  private static int[] intArray() {",
+            "    return new int[] {0, 1, CONST_INTEGER};",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"intArray\")",
+            "  void boxedInteger(Integer i) {}",
+            "",
+            "  private static LongStream longStream() {",
+            "    return LongStream.of(0, 1, CONST_LONG);",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"longStream\")",
+            "  void primitiveLong(long l) {}",
+            "",
+            "  private static long[] longArray() {",
+            "    return new long[] {0, 1, CONST_LONG};",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"longArray\")",
+            "  void boxedLong(Long l) {}",
+            "",
+            "  private static ImmutableList<Arguments> immutableListOfFloatArguments() {",
+            "    return ImmutableList.of(arguments(0.0F), arguments(1.0F), arguments(CONST_FLOAT));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"immutableListOfFloatArguments\")",
+            "  void primitiveFloat(float f) {}",
+            "",
+            "  private static Stream<Object> streamOfFloatsAndFloatArguments() {",
+            "    return Stream.of(0.0F, arguments(1.0F), CONST_FLOAT);",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"streamOfFloatsAndFloatArguments\")",
+            "  void boxedFloat(Float f) {}",
+            "",
+            "  private static DoubleStream doubleStream() {",
+            "    return DoubleStream.of(0, 1, CONST_DOUBLE);",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"doubleStream\")",
+            "  void primitiveDouble(double d) {}",
+            "",
+            "  private static double[] doubleArray() {",
+            "    return new double[] {0, 1, CONST_DOUBLE};",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"doubleArray\")",
+            "  void boxedDouble(Double d) {}",
+            "",
+            "  private static ImmutableSet<Arguments> immutableSetOfStringArguments() {",
+            "    return ImmutableSet.of(arguments(\"foo\"), arguments(\"bar\"), arguments(CONST_STRING));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"immutableSetOfStringArguments\")",
+            "  void string(String s) {}",
+            "",
+            "  private static Stream<Class<?>> streamOfClasses() {",
+            "    return Stream.of(Stream.class, java.util.Map.class);",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"streamOfClasses\")",
+            "  void clazz(Class<?> c) {}",
+            "",
+            "  private static Stream<Arguments> sameNameFactoryTestCases() {",
+            "    return Stream.of(arguments(1));",
+            "  }",
+            "",
+            "  private static Stream<Arguments> sameNameFactoryTestCases(int overload) {",
+            "    return Stream.of(arguments(overload));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @MethodSource(\"sameNameFactoryTestCases\")",
+            "  void sameNameFactory(int i) {}",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static org.junit.jupiter.params.provider.Arguments.arguments;",
+            "",
+            "import com.google.common.collect.ImmutableList;",
+            "import com.google.common.collect.ImmutableSet;",
+            "import java.util.List;",
+            "import java.util.Set;",
+            "import java.util.stream.DoubleStream;",
+            "import java.util.stream.IntStream;",
+            "import java.util.stream.LongStream;",
+            "import java.util.stream.Stream;",
+            "import org.junit.jupiter.params.ParameterizedTest;",
+            "import org.junit.jupiter.params.provider.Arguments;",
+            "import org.junit.jupiter.params.provider.MethodSource;",
+            "import org.junit.jupiter.params.provider.ValueSource;",
+            "",
+            "class A {",
+            "  private static final boolean CONST_BOOLEAN = false;",
+            "  private static final byte CONST_BYTE = 42;",
+            "  private static final char CONST_CHARACTER = 'a';",
+            "  private static final short CONST_SHORT = 42;",
+            "  private static final int CONST_INTEGER = 42;",
+            "  private static final long CONST_LONG = 42;",
+            "  private static final float CONST_FLOAT = 42;",
+            "  private static final double CONST_DOUBLE = 42;",
+            "  private static final String CONST_STRING = \"foo\";",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(booleans = {false, true, CONST_BOOLEAN})",
+            "  void primitiveBoolean(boolean b) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(booleans = {false, true, CONST_BOOLEAN})",
+            "  void boxedBoolean(Boolean b) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(bytes = {(byte) 0, (byte) 1, CONST_BYTE})",
+            "  void primitiveByte(byte b) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(bytes = {(byte) 0, (byte) 1, CONST_BYTE})",
+            "  void boxedByte(Byte b) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(chars = {(char) 0, (char) 1, CONST_CHARACTER})",
+            "  void primitiveCharacter(char c) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(chars = {(char) 0, (char) 1, CONST_CHARACTER})",
+            "  void boxedCharacter(Character c) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(shorts = {(short) 0, (short) 1, CONST_SHORT})",
+            "  void primitiveShort(short s) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(shorts = {(short) 0, (short) 1, CONST_SHORT})",
+            "  void boxedShort(Short s) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(ints = {0, 1, CONST_INTEGER})",
+            "  void primitiveInteger(int i) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(ints = {0, 1, CONST_INTEGER})",
+            "  void boxedInteger(Integer i) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(longs = {0, 1, CONST_LONG})",
+            "  void primitiveLong(long l) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(longs = {0, 1, CONST_LONG})",
+            "  void boxedLong(Long l) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(floats = {0.0F, 1.0F, CONST_FLOAT})",
+            "  void primitiveFloat(float f) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(floats = {0.0F, 1.0F, CONST_FLOAT})",
+            "  void boxedFloat(Float f) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(doubles = {0, 1, CONST_DOUBLE})",
+            "  void primitiveDouble(double d) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(doubles = {0, 1, CONST_DOUBLE})",
+            "  void boxedDouble(Double d) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(strings = {\"foo\", \"bar\", CONST_STRING})",
+            "  void string(String s) {}",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(classes = {Stream.class, java.util.Map.class})",
+            "  void clazz(Class<?> c) {}",
+            "",
+            "  private static Stream<Arguments> sameNameFactoryTestCases(int overload) {",
+            "    return Stream.of(arguments(overload));",
+            "  }",
+            "",
+            "  @ParameterizedTest",
+            "  @ValueSource(ints = 1)",
+            "  void sameNameFactory(int i) {}",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/MockitoMockClassReferenceTest.java

@@ -0,0 +1,136 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class MockitoMockClassReferenceTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(MockitoMockClassReference.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import static org.mockito.Mockito.mock;",
+            "import static org.mockito.Mockito.spy;",
+            "import static org.mockito.Mockito.withSettings;",
+            "",
+            "import java.util.List;",
+            "import java.util.Objects;",
+            "import org.mockito.invocation.InvocationOnMock;",
+            "",
+            "class A {",
+            "  {",
+            "    Double d = Objects.requireNonNullElseGet(null, () -> mock(Double.class));",
+            "    Double d2 =",
+            "        Objects.requireNonNullElseGet(",
+            "            null,",
+            "            () -> {",
+            "              return mock(Double.class);",
+            "            });",
+            "  }",
+            "",
+            "  void m() {",
+            "    Number variableMock = 42;",
+            "    // BUG: Diagnostic contains:",
+            "    variableMock = mock(Number.class);",
+            "    // BUG: Diagnostic contains:",
+            "    variableMock = mock(Number.class, \"name\");",
+            "    // BUG: Diagnostic contains:",
+            "    variableMock = mock(Number.class, InvocationOnMock::callRealMethod);",
+            "    // BUG: Diagnostic contains:",
+            "    variableMock = mock(Number.class, withSettings());",
+            "    variableMock = mock(Integer.class);",
+            "    variableMock = 42;",
+            "    // BUG: Diagnostic contains:",
+            "    List rawMock = mock(List.class);",
+            "    // BUG: Diagnostic contains:",
+            "    List<String> genericMock = mock(List.class);",
+            "    var varMock = mock(Integer.class);",
+            "    Class<? extends Number> numberType = Integer.class;",
+            "    Number variableTypeMock = mock(numberType);",
+            "    Object subtypeMock = mock(Integer.class);",
+            "",
+            "    Number variableSpy = 42;",
+            "    // BUG: Diagnostic contains:",
+            "    variableSpy = spy(Number.class);",
+            "    variableSpy = spy(Integer.class);",
+            "    variableSpy = 42;",
+            "    // BUG: Diagnostic contains:",
+            "    List rawSpy = spy(List.class);",
+            "    // BUG: Diagnostic contains:",
+            "    List<String> genericSpy = spy(List.class);",
+            "    var varSpy = spy(Integer.class);",
+            "    Number variableTypeSpy = spy(numberType);",
+            "    Object subtypeSpy = spy(Integer.class);",
+            "    Object objectSpy = spy(new Object());",
+            "",
+            "    Objects.hash(mock(Integer.class));",
+            "    Integer i = mock(mock(Integer.class));",
+            "    String s = new String(mock(String.class));",
+            "  }",
+            "",
+            "  Double getDoubleMock() {",
+            "    return Objects.requireNonNullElseGet(",
+            "        null,",
+            "        () -> {",
+            "          return mock(Double.class);",
+            "        });",
+            "  }",
+            "",
+            "  Integer getIntegerMock() {",
+            "    // BUG: Diagnostic contains:",
+            "    return mock(Integer.class);",
+            "  }",
+            "",
+            "  <T> T getGenericMock(Class<T> clazz) {",
+            "    return mock(clazz);",
+            "  }",
+            "",
+            "  Number getSubTypeMock() {",
+            "    return mock(Integer.class);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    BugCheckerRefactoringTestHelper.newInstance(MockitoMockClassReference.class, getClass())
+        .addInputLines(
+            "A.java",
+            "import static org.mockito.Mockito.mock;",
+            "import static org.mockito.Mockito.spy;",
+            "import static org.mockito.Mockito.withSettings;",
+            "",
+            "import org.mockito.invocation.InvocationOnMock;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Number simpleMock = mock(Number.class);",
+            "    Number namedMock = mock(Number.class, \"name\");",
+            "    Number customAnswerMock = mock(Number.class, InvocationOnMock::callRealMethod);",
+            "    Number customSettingsMock = mock(Number.class, withSettings());",
+            "    Number simpleSpy = spy(Number.class);",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static org.mockito.Mockito.mock;",
+            "import static org.mockito.Mockito.spy;",
+            "import static org.mockito.Mockito.withSettings;",
+            "",
+            "import org.mockito.invocation.InvocationOnMock;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Number simpleMock = mock();",
+            "    Number namedMock = mock(\"name\");",
+            "    Number customAnswerMock = mock(InvocationOnMock::callRealMethod);",
+            "    Number customSettingsMock = mock(withSettings());",
+            "    Number simpleSpy = spy();",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/RequestMappingAnnotationTest.java

@@ -16,6 +16,8 @@ final class RequestMappingAnnotationTest {
             "import javax.servlet.http.HttpServletRequest;",
             "import javax.servlet.http.HttpServletResponse;",
             "import org.springframework.http.HttpMethod;",
+            "import org.springframework.ui.Model;",
+            "import org.springframework.validation.BindingResult;",
             "import org.springframework.web.bind.annotation.DeleteMapping;",
             "import org.springframework.web.bind.annotation.GetMapping;",
             "import org.springframework.web.bind.annotation.PatchMapping;",
@@ -82,6 +84,12 @@ final class RequestMappingAnnotationTest {
             "  A properHttpMethod(HttpMethod method);",
             "",
             "  @RequestMapping",
+            "  A properModel(Model model);",
+            "",
+            "  @RequestMapping",
+            "  A properBindingResult(BindingResult result);",
+            "",
+            "  @RequestMapping",
             "  A properNativeWebRequest(NativeWebRequest request);",
             "",
             "  @RequestMapping",

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/StringCaseLocaleUsageTest.java

@@ -48,7 +48,6 @@ final class StringCaseLocaleUsageTest {
   @Test
   void replacementFirstSuggestedFix() {
     BugCheckerRefactoringTestHelper.newInstance(StringCaseLocaleUsage.class, getClass())
-        .setFixChooser(FixChoosers.FIRST)
         .addInputLines(
             "A.java",
             "class A {",

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/util/MoreASTHelpersTest.java

@@ -8,9 +8,16 @@ import com.google.errorprone.BugPattern;
 import com.google.errorprone.CompilationTestHelper;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.ExpressionStatementTreeMatcher;
 import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
+import com.google.errorprone.bugpatterns.BugChecker.ReturnTreeMatcher;
 import com.google.errorprone.matchers.Description;
+import com.sun.source.tree.ExpressionStatementTree;
 import com.sun.source.tree.MethodTree;
+import com.sun.source.tree.ReturnTree;
+import com.sun.source.tree.Tree;
+import com.sun.source.tree.VariableTree;
+import java.util.List;
 import java.util.function.BiFunction;
 import org.junit.jupiter.api.Test;
 
@@ -67,7 +74,70 @@ final class MoreASTHelpersTest {
         .doTest();
   }
 
-  private static String createDiagnosticsMessage(
+  @Test
+  void findMethodExitedOnReturn() {
+    CompilationTestHelper.newInstance(FindMethodReturnTestChecker.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import java.util.stream.Stream;",
+            "",
+            "class A {",
+            "  {",
+            "    toString();",
+            "  }",
+            "",
+            "  String topLevelMethod() {",
+            "    // BUG: Diagnostic contains: topLevelMethod",
+            "    toString();",
+            "    // BUG: Diagnostic contains: topLevelMethod",
+            "    return toString();",
+            "  }",
+            "",
+            "  Stream<String> anotherMethod() {",
+            "    // BUG: Diagnostic contains: anotherMethod",
+            "    return Stream.of(1)",
+            "        .map(",
+            "            n -> {",
+            "              toString();",
+            "              return toString();",
+            "            });",
+            "  }",
+            "",
+            "  void recursiveMethod(Runnable r) {",
+            "    // BUG: Diagnostic contains: recursiveMethod",
+            "    recursiveMethod(",
+            "        new Runnable() {",
+            "          @Override",
+            "          public void run() {",
+            "            // BUG: Diagnostic contains: run",
+            "            toString();",
+            "          }",
+            "        });",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void areSameType() {
+    CompilationTestHelper.newInstance(AreSameTypeTestChecker.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "class A {",
+            "  void negative1(String a, Integer b) {}",
+            "",
+            "  void negative2(Integer a, Number b) {}",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  void positive1(String a, String b) {}",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  void positive2(Iterable<String> a, Iterable<Integer> b) {}",
+            "}")
+        .doTest();
+  }
+
+  private static String createMethodSearchDiagnosticsMessage(
       BiFunction<String, VisitorState, Object> valueFunction, VisitorState state) {
     return Maps.toMap(ImmutableSet.of("foo", "bar", "baz"), key -> valueFunction.apply(key, state))
         .toString();
@@ -85,7 +155,7 @@ final class MoreASTHelpersTest {
     public Description matchMethod(MethodTree tree, VisitorState state) {
       return buildDescription(tree)
           .setMessage(
-              createDiagnosticsMessage(
+              createMethodSearchDiagnosticsMessage(
                   (methodName, s) -> MoreASTHelpers.findMethods(methodName, s).size(), state))
           .build();
     }
@@ -103,8 +173,55 @@ final class MoreASTHelpersTest {
     @Override
     public Description matchMethod(MethodTree tree, VisitorState state) {
       return buildDescription(tree)
-          .setMessage(createDiagnosticsMessage(MoreASTHelpers::methodExistsInEnclosingClass, state))
+          .setMessage(
+              createMethodSearchDiagnosticsMessage(
+                  MoreASTHelpers::methodExistsInEnclosingClass, state))
           .build();
     }
   }
+
+  /**
+   * A {@link BugChecker} that delegates to {@link
+   * MoreASTHelpers#findMethodExitedOnReturn(VisitorState)}.
+   */
+  @BugPattern(summary = "Interacts with `MoreASTHelpers` for testing purposes", severity = ERROR)
+  public static final class FindMethodReturnTestChecker extends BugChecker
+      implements ExpressionStatementTreeMatcher, ReturnTreeMatcher {
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    public Description matchExpressionStatement(ExpressionStatementTree tree, VisitorState state) {
+      return flagMethodReturnLocation(tree, state);
+    }
+
+    @Override
+    public Description matchReturn(ReturnTree tree, VisitorState state) {
+      return flagMethodReturnLocation(tree, state);
+    }
+
+    private Description flagMethodReturnLocation(Tree tree, VisitorState state) {
+      return MoreASTHelpers.findMethodExitedOnReturn(state)
+          .map(m -> buildDescription(tree).setMessage(m.getName().toString()).build())
+          .orElse(Description.NO_MATCH);
+    }
+  }
+
+  /**
+   * A {@link BugChecker} that delegates to {@link MoreASTHelpers#areSameType(Tree, Tree,
+   * VisitorState)}.
+   */
+  @BugPattern(summary = "Interacts with `MoreASTHelpers` for testing purposes", severity = ERROR)
+  public static final class AreSameTypeTestChecker extends BugChecker implements MethodTreeMatcher {
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    public Description matchMethod(MethodTree tree, VisitorState state) {
+      List<? extends VariableTree> parameters = tree.getParameters();
+      return parameters.stream()
+              .skip(1)
+              .allMatch(p -> MoreASTHelpers.areSameType(p, parameters.get(0), state))
+          ? describeMatch(tree)
+          : Description.NO_MATCH;
+    }
+  }
 }

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/util/MoreJUnitMatchersTest.java

@@ -83,6 +83,40 @@ final class MoreJUnitMatchersTest {
   @Test
   void getMethodSourceFactoryNames() {
     CompilationTestHelper.newInstance(MethodSourceFactoryNamesTestChecker.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import org.junit.jupiter.params.provider.MethodSource;",
+            "",
+            "class A {",
+            "  @MethodSource",
+            "  // BUG: Diagnostic contains: [matchingMethodSource]",
+            "  void matchingMethodSource(boolean b) {}",
+            "",
+            "  @MethodSource(\"myValueFactory\")",
+            "  // BUG: Diagnostic contains: [myValueFactory]",
+            "  void singleCustomMethodSource(boolean b) {}",
+            "",
+            "  @MethodSource({",
+            "    \"nullary()\",",
+            "    \"nullary()\",",
+            "    \"\",",
+            "    \"withStringParam(java.lang.String)\",",
+            "    \"paramsUnspecified\"",
+            "  })",
+            "  // BUG: Diagnostic contains: [nullary, nullary, multipleMethodSources, withStringParam,",
+            "  // paramsUnspecified]",
+            "  void multipleMethodSources(boolean b) {}",
+            "",
+            "  @MethodSource({\"foo\", \"()\", \"bar\"})",
+            "  // BUG: Diagnostic contains: [foo, , bar]",
+            "  void methodSourceWithoutName(boolean b) {}",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void getMethodSourceFactoryDescriptors() {
+    CompilationTestHelper.newInstance(MethodSourceFactoryDescriptorsTestChecker.class, getClass())
         .addSourceLines(
             "A.java",
             "import org.junit.jupiter.params.provider.MethodSource;",
@@ -119,6 +153,14 @@ final class MoreJUnitMatchersTest {
             "  @MethodSource({\"myValueFactory\", \"\"})",
             "  // BUG: Diagnostic contains: [myValueFactory, customAndMatchingMethodSources]",
             "  void customAndMatchingMethodSources(boolean b) {}",
+            "",
+            "  @MethodSource({\"factory\", \"\", \"factory\", \"\"})",
+            "  // BUG: Diagnostic contains: [factory, repeatedMethodSources, factory, repeatedMethodSources]",
+            "  void repeatedMethodSources(boolean b) {}",
+            "",
+            "  @MethodSource({\"nullary()\", \"withStringParam(java.lang.String)\"})",
+            "  // BUG: Diagnostic contains: [nullary(), withStringParam(java.lang.String)]",
+            "  void methodSourcesWithParameterSpecification(boolean b) {}",
             "}")
         .doTest();
   }
@@ -170,4 +212,25 @@ final class MoreJUnitMatchersTest {
           .build();
     }
   }
+
+  /**
+   * A {@link BugChecker} that flags methods with a JUnit {@code @MethodSource} annotation by
+   * enumerating the associated value factory method descriptors.
+   */
+  @BugPattern(summary = "Interacts with `MoreJUnitMatchers` for testing purposes", severity = ERROR)
+  public static final class MethodSourceFactoryDescriptorsTestChecker extends BugChecker
+      implements MethodTreeMatcher {
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    public Description matchMethod(MethodTree tree, VisitorState state) {
+      AnnotationTree annotation =
+          Iterables.getOnlyElement(HAS_METHOD_SOURCE.multiMatchResult(tree, state).matchingNodes());
+
+      return buildDescription(tree)
+          .setMessage(
+              MoreJUnitMatchers.getMethodSourceFactoryDescriptors(annotation, tree).toString())
+          .build();
+    }
+  }
 }

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/util/SourceCodeTest.java

@@ -31,7 +31,6 @@ final class SourceCodeTest {
         .expectUnchanged()
         .addInputLines(
             "AnnotationDeletions.java",
-            "",
             "interface AnnotationDeletions {",
             "  class SoleAnnotation {",
             "    @AnnotationToBeDeleted",
@@ -66,7 +65,6 @@ final class SourceCodeTest {
             "}")
         .addOutputLines(
             "AnnotationDeletions.java",
-            "",
             "interface AnnotationDeletions {",
             "  class SoleAnnotation {",
             "    void m() {}",
@@ -101,7 +99,6 @@ final class SourceCodeTest {
     refactoringTestHelper
         .addInputLines(
             "MethodDeletions.java",
-            "",
             "interface MethodDeletions {",
             "  class SoleMethod {",
             "    void methodToBeDeleted() {}",
@@ -141,7 +138,6 @@ final class SourceCodeTest {
             "}")
         .addOutputLines(
             "MethodDeletions.java",
-            "",
             "interface MethodDeletions {",
             "  class SoleMethod {}",
             "",

error-prone-contrib/src/test/java/tech/picnic/errorprone/refasterrules/RefasterRulesTest.java

@@ -35,6 +35,7 @@ final class RefasterRulesTest {
           AssertJThrowingCallableRules.class,
           AssortedRules.class,
           BigDecimalRules.class,
+          BugCheckerRules.class,
           CollectionRules.class,
           ComparatorRules.class,
           DoubleStreamRules.class,

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/AssertJStringRulesTestInput.java

@@ -2,11 +2,21 @@ package tech.picnic.errorprone.refasterrules;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+import com.google.common.collect.ImmutableSet;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import org.assertj.core.api.AbstractAssert;
 import org.assertj.core.api.AbstractStringAssert;
 import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
 
 final class AssertJStringRulesTest implements RefasterRuleCollectionTestCase {
+  @Override
+  public ImmutableSet<?> elidedTypesAndStaticImports() {
+    return ImmutableSet.of(Files.class);
+  }
+
   void testAbstractStringAssertStringIsEmpty() {
     assertThat("foo").isEqualTo("");
   }
@@ -30,4 +40,12 @@ final class AssertJStringRulesTest implements RefasterRuleCollectionTestCase {
   AbstractAssert<?, ?> testAssertThatDoesNotMatch() {
     return assertThat("foo".matches(".*")).isFalse();
   }
+
+  AbstractStringAssert<?> testAssertThatPathContent() throws IOException {
+    return assertThat(Files.readString(Paths.get(""), Charset.defaultCharset()));
+  }
+
+  AbstractStringAssert<?> testAssertThatPathContentUtf8() throws IOException {
+    return assertThat(Files.readString(Paths.get("")));
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/AssertJStringRulesTestOutput.java

@@ -1,12 +1,23 @@
 package tech.picnic.errorprone.refasterrules;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.assertj.core.api.Assertions.assertThat;
 
+import com.google.common.collect.ImmutableSet;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import org.assertj.core.api.AbstractAssert;
 import org.assertj.core.api.AbstractStringAssert;
 import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
 
 final class AssertJStringRulesTest implements RefasterRuleCollectionTestCase {
+  @Override
+  public ImmutableSet<?> elidedTypesAndStaticImports() {
+    return ImmutableSet.of(Files.class);
+  }
+
   void testAbstractStringAssertStringIsEmpty() {
     assertThat("foo").isEmpty();
   }
@@ -30,4 +41,12 @@ final class AssertJStringRulesTest implements RefasterRuleCollectionTestCase {
   AbstractAssert<?, ?> testAssertThatDoesNotMatch() {
     return assertThat("foo").doesNotMatch(".*");
   }
+
+  AbstractStringAssert<?> testAssertThatPathContent() throws IOException {
+    return assertThat(Paths.get("")).content(Charset.defaultCharset());
+  }
+
+  AbstractStringAssert<?> testAssertThatPathContentUtf8() throws IOException {
+    return assertThat(Paths.get("")).content(UTF_8);
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/BugCheckerRulesTestInput.java

@@ -0,0 +1,29 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;
+import com.google.errorprone.bugpatterns.BugChecker;
+import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
+
+final class BugCheckerRulesTest implements RefasterRuleCollectionTestCase {
+  @Override
+  public ImmutableSet<?> elidedTypesAndStaticImports() {
+    return ImmutableSet.of(FixChoosers.class);
+  }
+
+  ImmutableSet<BugCheckerRefactoringTestHelper> testBugCheckerRefactoringTestHelperIdentity() {
+    return ImmutableSet.of(
+        BugCheckerRefactoringTestHelper.newInstance(BugChecker.class, getClass())
+            .setFixChooser(FixChoosers.FIRST),
+        BugCheckerRefactoringTestHelper.newInstance(BugChecker.class, getClass())
+            .setImportOrder("static-first"));
+  }
+
+  BugCheckerRefactoringTestHelper
+      testBugCheckerRefactoringTestHelperAddInputLinesExpectUnchanged() {
+    return BugCheckerRefactoringTestHelper.newInstance(BugChecker.class, getClass())
+        .addInputLines("A.java", "class A {}")
+        .addOutputLines("A.java", "class A {}");
+  }
+}

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/BugCheckerRulesTestOutput.java

@@ -0,0 +1,27 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;
+import com.google.errorprone.bugpatterns.BugChecker;
+import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
+
+final class BugCheckerRulesTest implements RefasterRuleCollectionTestCase {
+  @Override
+  public ImmutableSet<?> elidedTypesAndStaticImports() {
+    return ImmutableSet.of(FixChoosers.class);
+  }
+
+  ImmutableSet<BugCheckerRefactoringTestHelper> testBugCheckerRefactoringTestHelperIdentity() {
+    return ImmutableSet.of(
+        BugCheckerRefactoringTestHelper.newInstance(BugChecker.class, getClass()),
+        BugCheckerRefactoringTestHelper.newInstance(BugChecker.class, getClass()));
+  }
+
+  BugCheckerRefactoringTestHelper
+      testBugCheckerRefactoringTestHelperAddInputLinesExpectUnchanged() {
+    return BugCheckerRefactoringTestHelper.newInstance(BugChecker.class, getClass())
+        .addInputLines("A.java", "class A {}")
+        .expectUnchanged();
+  }
+}

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/ImmutableMapRulesTestInput.java

@@ -107,4 +107,16 @@ final class ImmutableMapRulesTest implements RefasterRuleCollectionTestCase {
   Map<String, String> testImmutableMapOf5() {
     return Map.of("k1", "v1", "k2", "v2", "k3", "v3", "k4", "v4", "k5", "v5");
   }
+
+  ImmutableMap<String, Integer> testImmutableMapCopyOfMapsFilterKeys() {
+    return ImmutableMap.of("foo", 1).entrySet().stream()
+        .filter(entry -> entry.getKey().length() > 1)
+        .collect(toImmutableMap(Map.Entry::getKey, Map.Entry::getValue));
+  }
+
+  ImmutableMap<String, Integer> testImmutableMapCopyOfMapsFilterValues() {
+    return ImmutableMap.of("foo", 1).entrySet().stream()
+        .filter(entry -> entry.getValue() > 0)
+        .collect(toImmutableMap(Map.Entry::getKey, Map.Entry::getValue));
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/ImmutableMapRulesTestOutput.java

@@ -90,4 +90,12 @@ final class ImmutableMapRulesTest implements RefasterRuleCollectionTestCase {
   Map<String, String> testImmutableMapOf5() {
     return ImmutableMap.of("k1", "v1", "k2", "v2", "k3", "v3", "k4", "v4", "k5", "v5");
   }
+
+  ImmutableMap<String, Integer> testImmutableMapCopyOfMapsFilterKeys() {
+    return ImmutableMap.copyOf(Maps.filterKeys(ImmutableMap.of("foo", 1), k -> k.length() > 1));
+  }
+
+  ImmutableMap<String, Integer> testImmutableMapCopyOfMapsFilterValues() {
+    return ImmutableMap.copyOf(Maps.filterValues(ImmutableMap.of("foo", 1), v -> v > 0));
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/NullRulesTestInput.java

@@ -13,12 +13,12 @@ final class NullRulesTest implements RefasterRuleCollectionTestCase {
     return ImmutableSet.of(MoreObjects.class, Optional.class);
   }
 
-  boolean testIsNull() {
-    return Objects.isNull("foo");
+  ImmutableSet<Boolean> testIsNull() {
+    return ImmutableSet.of(null == "foo", Objects.isNull("bar"));
   }
 
-  boolean testIsNotNull() {
-    return Objects.nonNull("foo");
+  ImmutableSet<Boolean> testIsNotNull() {
+    return ImmutableSet.of(null != "foo", Objects.nonNull("bar"));
   }
 
   ImmutableSet<String> testRequireNonNullElse() {

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/NullRulesTestOutput.java

@@ -16,12 +16,12 @@ final class NullRulesTest implements RefasterRuleCollectionTestCase {
     return ImmutableSet.of(MoreObjects.class, Optional.class);
   }
 
-  boolean testIsNull() {
-    return "foo" == null;
+  ImmutableSet<Boolean> testIsNull() {
+    return ImmutableSet.of("foo" == null, "bar" == null);
   }
 
-  boolean testIsNotNull() {
-    return "foo" != null;
+  ImmutableSet<Boolean> testIsNotNull() {
+    return ImmutableSet.of("foo" != null, "bar" != null);
   }
 
   ImmutableSet<String> testRequireNonNullElse() {

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/PreconditionsRulesTestInput.java

@@ -1,8 +1,17 @@
 package tech.picnic.errorprone.refasterrules;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.collect.ImmutableSet;
 import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
 
 final class PreconditionsRulesTest implements RefasterRuleCollectionTestCase {
+  @Override
+  @SuppressWarnings("RequireNonNull")
+  public ImmutableSet<?> elidedTypesAndStaticImports() {
+    return ImmutableSet.of(checkNotNull(null));
+  }
+
   void testCheckArgument() {
     if ("foo".isEmpty()) {
       throw new IllegalArgumentException();
@@ -21,13 +30,21 @@ final class PreconditionsRulesTest implements RefasterRuleCollectionTestCase {
     }
   }
 
-  void testCheckNotNull() {
+  String testRequireNonNull() {
+    return checkNotNull("foo");
+  }
+
+  void testRequireNonNullStatement() {
     if ("foo" == null) {
       throw new NullPointerException();
     }
   }
 
-  void testCheckNotNullWithMessage() {
+  String testRequireNonNullWithMessage() {
+    return checkNotNull("foo", "The string is null");
+  }
+
+  void testRequireNonNullWithMessageStatement() {
     if ("foo" == null) {
       throw new NullPointerException("The string is null");
     }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/PreconditionsRulesTestOutput.java

@@ -5,10 +5,18 @@ import static com.google.common.base.Preconditions.checkElementIndex;
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.base.Preconditions.checkPositionIndex;
 import static com.google.common.base.Preconditions.checkState;
+import static java.util.Objects.requireNonNull;
 
+import com.google.common.collect.ImmutableSet;
 import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
 
 final class PreconditionsRulesTest implements RefasterRuleCollectionTestCase {
+  @Override
+  @SuppressWarnings("RequireNonNull")
+  public ImmutableSet<?> elidedTypesAndStaticImports() {
+    return ImmutableSet.of(checkNotNull(null));
+  }
+
   void testCheckArgument() {
     checkArgument(!"foo".isEmpty());
   }
@@ -21,12 +29,20 @@ final class PreconditionsRulesTest implements RefasterRuleCollectionTestCase {
     checkElementIndex(1, 2, "My index");
   }
 
-  void testCheckNotNull() {
-    checkNotNull("foo");
+  String testRequireNonNull() {
+    return requireNonNull("foo");
   }
 
-  void testCheckNotNullWithMessage() {
-    checkNotNull("foo", "The string is null");
+  void testRequireNonNullStatement() {
+    requireNonNull("foo");
+  }
+
+  String testRequireNonNullWithMessage() {
+    return requireNonNull("foo", "The string is null");
+  }
+
+  void testRequireNonNullWithMessageStatement() {
+    requireNonNull("foo", "The string is null");
   }
 
   void testCheckPositionIndex() {

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/ReactorRulesTestInput.java

@@ -1,14 +1,21 @@
 package tech.picnic.errorprone.refasterrules;
 
+import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.common.collect.MoreCollectors.toOptional;
 import static java.util.Comparator.reverseOrder;
 import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.toCollection;
 import static org.assertj.core.api.Assertions.assertThat;
 
+import com.google.common.collect.ImmutableCollection;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import java.time.Duration;
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Optional;
 import java.util.concurrent.Callable;
 import java.util.function.Supplier;
@@ -23,7 +30,17 @@ import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
 final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
   @Override
   public ImmutableSet<?> elidedTypesAndStaticImports() {
-    return ImmutableSet.of(assertThat(0), HashMap.class, ImmutableMap.class);
+    return ImmutableSet.of(
+        ArrayList.class,
+        Collection.class,
+        HashMap.class,
+        List.class,
+        ImmutableCollection.class,
+        ImmutableMap.class,
+        assertThat(0),
+        toCollection(null),
+        toImmutableList(),
+        toOptional());
   }
 
   ImmutableSet<Mono<?>> testMonoFromSupplier() {
@@ -229,8 +246,10 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return Mono.just("foo").flux().then();
   }
 
-  Mono<Optional<String>> testMonoCollectToOptional() {
-    return Mono.just("foo").map(Optional::of).defaultIfEmpty(Optional.empty());
+  ImmutableSet<Mono<Optional<String>>> testMonoSingleOptional() {
+    return ImmutableSet.of(
+        Mono.just("foo").flux().collect(toOptional()),
+        Mono.just("bar").map(Optional::of).defaultIfEmpty(Optional.empty()));
   }
 
   Mono<Number> testMonoCast() {
@@ -261,6 +280,16 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
         Flux.just(ImmutableList.of("bar")).concatMap(Flux::fromIterable, 2));
   }
 
+  ImmutableSet<Mono<Integer>> testFluxCountMapMathToIntExact() {
+    return ImmutableSet.of(
+        Flux.just(1).collect(toImmutableList()).map(Collection::size),
+        Flux.just(2).collect(toImmutableList()).map(List::size),
+        Flux.just(3).collect(toImmutableList()).map(ImmutableCollection::size),
+        Flux.just(4).collect(toImmutableList()).map(ImmutableList::size),
+        Flux.just(5).collect(toCollection(ArrayList::new)).map(Collection::size),
+        Flux.just(6).collect(toCollection(ArrayList::new)).map(List::size));
+  }
+
   Mono<Integer> testMonoDoOnError() {
     return Mono.just(1).doOnError(IllegalArgumentException.class::isInstance, e -> {});
   }
@@ -360,8 +389,10 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return StepVerifier.create(Flux.just(1));
   }
 
-  StepVerifier.Step<Integer> testStepVerifierStepExpectNextEmpty() {
-    return StepVerifier.create(Mono.just(0)).expectNext();
+  ImmutableSet<StepVerifier.Step<Integer>> testStepVerifierStepIdentity() {
+    return ImmutableSet.of(
+        StepVerifier.create(Mono.just(1)).expectNext(),
+        StepVerifier.create(Mono.just(2)).expectNextCount(0L));
   }
 
   ImmutableSet<StepVerifier.Step<String>> testStepVerifierStepExpectNext() {

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/ReactorRulesTestOutput.java

@@ -1,16 +1,22 @@
 package tech.picnic.errorprone.refasterrules;
 
+import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.MoreCollectors.toOptional;
 import static java.util.Comparator.reverseOrder;
 import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.toCollection;
 import static org.assertj.core.api.Assertions.assertThat;
 import static reactor.function.TupleUtils.function;
 
+import com.google.common.collect.ImmutableCollection;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import java.time.Duration;
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Optional;
 import java.util.concurrent.Callable;
 import java.util.function.Supplier;
@@ -26,7 +32,17 @@ import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
 final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
   @Override
   public ImmutableSet<?> elidedTypesAndStaticImports() {
-    return ImmutableSet.of(assertThat(0), HashMap.class, ImmutableMap.class);
+    return ImmutableSet.of(
+        ArrayList.class,
+        Collection.class,
+        HashMap.class,
+        List.class,
+        ImmutableCollection.class,
+        ImmutableMap.class,
+        assertThat(0),
+        toCollection(null),
+        toImmutableList(),
+        toOptional());
   }
 
   ImmutableSet<Mono<?>> testMonoFromSupplier() {
@@ -224,8 +240,8 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return Mono.just("foo").then();
   }
 
-  Mono<Optional<String>> testMonoCollectToOptional() {
-    return Mono.just("foo").flux().collect(toOptional());
+  ImmutableSet<Mono<Optional<String>>> testMonoSingleOptional() {
+    return ImmutableSet.of(Mono.just("foo").singleOptional(), Mono.just("bar").singleOptional());
   }
 
   Mono<Number> testMonoCast() {
@@ -256,6 +272,16 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
         Flux.just(ImmutableList.of("bar")).concatMapIterable(identity(), 2));
   }
 
+  ImmutableSet<Mono<Integer>> testFluxCountMapMathToIntExact() {
+    return ImmutableSet.of(
+        Flux.just(1).count().map(Math::toIntExact),
+        Flux.just(2).count().map(Math::toIntExact),
+        Flux.just(3).count().map(Math::toIntExact),
+        Flux.just(4).count().map(Math::toIntExact),
+        Flux.just(5).count().map(Math::toIntExact),
+        Flux.just(6).count().map(Math::toIntExact));
+  }
+
   Mono<Integer> testMonoDoOnError() {
     return Mono.just(1).doOnError(IllegalArgumentException.class, e -> {});
   }
@@ -351,8 +377,8 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return Flux.just(1).as(StepVerifier::create);
   }
 
-  StepVerifier.Step<Integer> testStepVerifierStepExpectNextEmpty() {
-    return StepVerifier.create(Mono.just(0));
+  ImmutableSet<StepVerifier.Step<Integer>> testStepVerifierStepIdentity() {
+    return ImmutableSet.of(StepVerifier.create(Mono.just(1)), StepVerifier.create(Mono.just(2)));
   }
 
   ImmutableSet<StepVerifier.Step<String>> testStepVerifierStepExpectNext() {

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/StreamRulesTestInput.java

@@ -9,6 +9,7 @@ import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Streams;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
@@ -138,4 +139,28 @@ final class StreamRulesTest implements RefasterRuleCollectionTestCase {
   boolean testStreamAllMatch2() {
     return Stream.of("foo").noneMatch(s -> !s.isBlank());
   }
+
+  ImmutableSet<Integer> testStreamMapToIntSum() {
+    Function<String, Integer> parseIntFunction = Integer::parseInt;
+    return ImmutableSet.of(
+        Stream.of(1).map(i -> i * 2).reduce(0, Integer::sum),
+        Stream.of("2").map(Integer::parseInt).reduce(0, Integer::sum),
+        Stream.of("3").map(parseIntFunction).reduce(0, Integer::sum));
+  }
+
+  ImmutableSet<Double> testStreamMapToDoubleSum() {
+    Function<String, Double> parseDoubleFunction = Double::parseDouble;
+    return ImmutableSet.of(
+        Stream.of(1).map(i -> i * 2.0).reduce(0.0, Double::sum),
+        Stream.of("2").map(Double::parseDouble).reduce(0.0, Double::sum),
+        Stream.of("3").map(parseDoubleFunction).reduce(0.0, Double::sum));
+  }
+
+  ImmutableSet<Long> testStreamMapToLongSum() {
+    Function<String, Long> parseLongFunction = Long::parseLong;
+    return ImmutableSet.of(
+        Stream.of(1).map(i -> i * 2L).reduce(0L, Long::sum),
+        Stream.of("2").map(Long::parseLong).reduce(0L, Long::sum),
+        Stream.of("3").map(parseLongFunction).reduce(0L, Long::sum));
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/StreamRulesTestOutput.java

@@ -11,6 +11,7 @@ import com.google.common.collect.Streams;
 import java.util.Arrays;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
@@ -137,4 +138,28 @@ final class StreamRulesTest implements RefasterRuleCollectionTestCase {
   boolean testStreamAllMatch2() {
     return Stream.of("foo").allMatch(s -> s.isBlank());
   }
+
+  ImmutableSet<Integer> testStreamMapToIntSum() {
+    Function<String, Integer> parseIntFunction = Integer::parseInt;
+    return ImmutableSet.of(
+        Stream.of(1).mapToInt(i -> i * 2).sum(),
+        Stream.of("2").mapToInt(Integer::parseInt).sum(),
+        Stream.of("3").map(parseIntFunction).reduce(0, Integer::sum));
+  }
+
+  ImmutableSet<Double> testStreamMapToDoubleSum() {
+    Function<String, Double> parseDoubleFunction = Double::parseDouble;
+    return ImmutableSet.of(
+        Stream.of(1).mapToDouble(i -> i * 2.0).sum(),
+        Stream.of("2").mapToDouble(Double::parseDouble).sum(),
+        Stream.of("3").map(parseDoubleFunction).reduce(0.0, Double::sum));
+  }
+
+  ImmutableSet<Long> testStreamMapToLongSum() {
+    Function<String, Long> parseLongFunction = Long::parseLong;
+    return ImmutableSet.of(
+        Stream.of(1).mapToLong(i -> i * 2L).sum(),
+        Stream.of("2").mapToLong(Long::parseLong).sum(),
+        Stream.of("3").map(parseLongFunction).reduce(0L, Long::sum));
+  }
 }

pom.xml

@@ -4,7 +4,7 @@
 
     <groupId>tech.picnic.error-prone-support</groupId>
     <artifactId>error-prone-support</artifactId>
-    <version>0.8.1-SNAPSHOT</version>
+    <version>0.9.0</version>
     <packaging>pom</packaging>
 
     <name>Picnic :: Error Prone Support</name>
@@ -49,7 +49,7 @@
 
     <scm>
         <developerConnection>scm:git:git@github.com:PicnicSupermarket/error-prone-support.git</developerConnection>
-        <tag>HEAD</tag>
+        <tag>v0.9.0</tag>
         <url>https://github.com/PicnicSupermarket/error-prone-support</url>
     </scm>
     <issueManagement>
@@ -141,7 +141,7 @@
         <groupId.error-prone>com.google.errorprone</groupId.error-prone>
         <!-- The build timestamp is derived from the most recent commit
         timestamp in support of reproducible builds. -->
-        <project.build.outputTimestamp>${git.commit.time}</project.build.outputTimestamp>
+        <project.build.outputTimestamp>2023-03-31T07:29:10Z</project.build.outputTimestamp>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <!-- Dependency and plugin versions that are referenced in more than
         one place. We use these to keep dependencies in sync. Version numbers
@@ -155,11 +155,11 @@
         <version.guava-beta-checker>1.0</version.guava-beta-checker>
         <version.jdk>11</version.jdk>
         <version.maven>3.8.7</version.maven>
-        <version.mockito>5.1.1</version.mockito>
+        <version.mockito>5.2.0</version.mockito>
         <version.nopen-checker>1.0.1</version.nopen-checker>
-        <version.nullaway>0.10.9</version.nullaway>
-        <version.pitest-git>1.0.4</version.pitest-git>
-        <version.surefire>2.22.2</version.surefire>
+        <version.nullaway>0.10.10</version.nullaway>
+        <version.pitest-git>1.0.7</version.pitest-git>
+        <version.surefire>3.0.0</version.surefire>
     </properties>
 
     <dependencyManagement>
@@ -244,7 +244,7 @@
             <dependency>
                 <groupId>com.google.googlejavaformat</groupId>
                 <artifactId>google-java-format</artifactId>
-                <version>1.15.0</version>
+                <version>1.16.0</version>
             </dependency>
             <!-- Specified as a workaround for
             https://github.com/mojohaus/versions-maven-plugin/issues/244. -->
@@ -275,7 +275,7 @@
             <dependency>
                 <groupId>com.newrelic.agent.java</groupId>
                 <artifactId>newrelic-api</artifactId>
-                <version>8.0.0</version>
+                <version>8.0.1</version>
             </dependency>
             <!-- Specified as a workaround for
             https://github.com/mojohaus/versions-maven-plugin/issues/244. -->
@@ -287,7 +287,7 @@
             <dependency>
                 <groupId>io.projectreactor</groupId>
                 <artifactId>reactor-bom</artifactId>
-                <version>2022.0.2</version>
+                <version>2022.0.5</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
@@ -299,12 +299,12 @@
             <dependency>
                 <groupId>io.swagger</groupId>
                 <artifactId>swagger-annotations</artifactId>
-                <version>1.6.9</version>
+                <version>1.6.10</version>
             </dependency>
             <dependency>
                 <groupId>io.swagger.core.v3</groupId>
                 <artifactId>swagger-annotations</artifactId>
-                <version>2.2.8</version>
+                <version>2.2.9</version>
             </dependency>
             <dependency>
                 <groupId>jakarta.servlet</groupId>
@@ -331,7 +331,7 @@
             <dependency>
                 <groupId>net.bytebuddy</groupId>
                 <artifactId>byte-buddy</artifactId>
-                <version>1.13.0</version>
+                <version>1.14.3</version>
             </dependency>
             <!-- Specified so that Renovate will file Maven upgrade PRs, which
             subsequently will cause `maven-enforcer-plugin` to require that
@@ -356,7 +356,7 @@
             <dependency>
                 <groupId>org.checkerframework</groupId>
                 <artifactId>checker-qual</artifactId>
-                <version>3.30.0</version>
+                <version>3.32.0</version>
             </dependency>
             <dependency>
                 <groupId>org.hamcrest</groupId>
@@ -390,19 +390,19 @@
             <dependency>
                 <groupId>org.slf4j</groupId>
                 <artifactId>slf4j-api</artifactId>
-                <version>2.0.6</version>
+                <version>2.0.7</version>
             </dependency>
             <dependency>
                 <groupId>org.springframework</groupId>
                 <artifactId>spring-framework-bom</artifactId>
-                <version>5.3.25</version>
+                <version>5.3.26</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
             <dependency>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-test</artifactId>
-                <version>2.7.8</version>
+                <version>2.7.10</version>
             </dependency>
             <dependency>
                 <groupId>org.testng</groupId>
@@ -467,7 +467,7 @@
                 <plugin>
                     <groupId>de.thetaphi</groupId>
                     <artifactId>forbiddenapis</artifactId>
-                    <version>3.4</version>
+                    <version>3.5</version>
                     <configuration>
                         <bundledSignatures>
                             <bundledSignature>jdk-internal</bundledSignature>
@@ -783,7 +783,7 @@
                         <dependency>
                             <groupId>com.puppycrawl.tools</groupId>
                             <artifactId>checkstyle</artifactId>
-                            <version>10.7.0</version>
+                            <version>10.9.3</version>
                         </dependency>
                         <dependency>
                             <groupId>io.spring.nohttp</groupId>
@@ -862,8 +862,8 @@
                         </annotationProcessorPaths>
                         <compilerArgs>
                             <arg>--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED</arg>
-                            <arg>--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED</arg>
                             <arg>--add-exports=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED</arg>
+                            <arg>--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED</arg>
                             <arg>--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED</arg>
                             <arg>--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED</arg>
                             <arg>--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED</arg>
@@ -899,7 +899,7 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-deploy-plugin</artifactId>
-                    <version>3.1.0</version>
+                    <version>3.1.1</version>
                     <configuration>
                         <retryFailedDeploymentCount>3</retryFailedDeploymentCount>
                     </configuration>
@@ -973,7 +973,7 @@
                         <dependency>
                             <groupId>org.codehaus.mojo</groupId>
                             <artifactId>extra-enforcer-rules</artifactId>
-                            <version>1.6.1</version>
+                            <version>1.6.2</version>
                         </dependency>
                     </dependencies>
                     <executions>
@@ -1001,7 +1001,7 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-install-plugin</artifactId>
-                    <version>3.1.0</version>
+                    <version>3.1.1</version>
                 </plugin>
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
@@ -1034,7 +1034,7 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-javadoc-plugin</artifactId>
-                    <version>3.4.1</version>
+                    <version>3.5.0</version>
                     <configuration>
                         <additionalJOptions>
                             <additionalJOption>--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED</additionalJOption>
@@ -1063,9 +1063,10 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-release-plugin</artifactId>
-                    <version>2.5.3</version>
+                    <version>3.0.0</version>
                     <configuration>
                         <autoVersionSubmodules>true</autoVersionSubmodules>
+                        <preparationProfiles>release</preparationProfiles>
                         <releaseProfiles>release</releaseProfiles>
                         <tagNameFormat>v@{project.version}</tagNameFormat>
                     </configuration>
@@ -1073,7 +1074,7 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-resources-plugin</artifactId>
-                    <version>3.3.0</version>
+                    <version>3.3.1</version>
                     <configuration>
                         <delimiters>
                             <delimiter>@</delimiter>
@@ -1109,24 +1110,11 @@
                             <include>**/*Test.java</include>
                         </includes>
                         <properties>
-                            <configurationParameters>junit.jupiter.execution.parallel.config.strategy=dynamic
-                                junit.jupiter.execution.parallel.enabled=true
-                                junit.jupiter.execution.parallel.mode.default = concurrent</configurationParameters>
+                            <configurationParameters>junit.jupiter.execution.parallel.enabled=true
+                                junit.jupiter.execution.parallel.mode.default=concurrent</configurationParameters>
                         </properties>
                         <redirectTestOutputToFile>true</redirectTestOutputToFile>
-                        <trimStackTrace>false</trimStackTrace>
                     </configuration>
-                    <dependencies>
-                        <!-- Some dependencies pull in JUnit 4; having it on
-                        the classpath confuses Surefire. By declaring this
-                        dependency we ensure that the JUnit 5 test runner is
-                        used. -->
-                        <dependency>
-                            <groupId>org.apache.maven.surefire</groupId>
-                            <artifactId>surefire-junit-platform</artifactId>
-                            <version>${version.surefire}</version>
-                        </dependency>
-                    </dependencies>
                 </plugin>
                 <plugin>
                     <groupId>org.codehaus.mojo</groupId>
@@ -1239,7 +1227,7 @@
                 <plugin>
                     <groupId>org.codehaus.mojo</groupId>
                     <artifactId>versions-maven-plugin</artifactId>
-                    <version>2.14.2</version>
+                    <version>2.15.0</version>
                     <configuration>
                         <updateBuildOutputTimestampPolicy>never</updateBuildOutputTimestampPolicy>
                     </configuration>
@@ -1247,7 +1235,7 @@
                 <plugin>
                     <groupId>org.gaul</groupId>
                     <artifactId>modernizer-maven-plugin</artifactId>
-                    <version>2.5.0</version>
+                    <version>2.6.0</version>
                     <configuration>
                         <exclusionPatterns>
                             <!-- The plugin suggests replacing usages of
@@ -1283,7 +1271,7 @@
                 <plugin>
                     <groupId>org.pitest</groupId>
                     <artifactId>pitest-maven</artifactId>
-                    <version>1.11.0</version>
+                    <version>1.11.7</version>
                     <configuration>
                         <excludedClasses>
                             <!-- AutoValue generated classes. -->

refaster-compiler/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.8.1-SNAPSHOT</version>
+        <version>0.9.0</version>
     </parent>
 
     <artifactId>refaster-compiler</artifactId>

refaster-runner/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.8.1-SNAPSHOT</version>
+        <version>0.9.0</version>
     </parent>
 
     <artifactId>refaster-runner</artifactId>

refaster-support/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.8.1-SNAPSHOT</version>
+        <version>0.9.0</version>
     </parent>
 
     <artifactId>refaster-support</artifactId>

refaster-support/src/main/java/tech/picnic/errorprone/refaster/matchers/IsLambdaExpressionOrMethodReference.java

@@ -0,0 +1,20 @@
+package tech.picnic.errorprone.refaster.matchers;
+
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.matchers.Matcher;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.LambdaExpressionTree;
+import com.sun.source.tree.MemberReferenceTree;
+
+/** A matcher of lambda expressions and method references. */
+public final class IsLambdaExpressionOrMethodReference implements Matcher<ExpressionTree> {
+  private static final long serialVersionUID = 1L;
+
+  /** Instantiates a new {@link IsLambdaExpressionOrMethodReference} instance. */
+  public IsLambdaExpressionOrMethodReference() {}
+
+  @Override
+  public boolean matches(ExpressionTree tree, VisitorState state) {
+    return tree instanceof LambdaExpressionTree || tree instanceof MemberReferenceTree;
+  }
+}

refaster-support/src/test/java/tech/picnic/errorprone/refaster/AnnotatedCompositeCodeTransformerTest.java

@@ -40,9 +40,9 @@ import tech.picnic.errorprone.refaster.annotation.Severity;
 // through `RefasterTest`, but ideally it is covered by tests in this class, closer to the code that
 // implements the relevant logic.) See the comment in `#context()` below.
 final class AnnotatedCompositeCodeTransformerTest {
-  private static final DiagnosticPosition DUMMY_POSITION = mock(DiagnosticPosition.class);
-  private static final Fix DUMMY_FIX = mock(Fix.class);
-  private static final TreePath DUMMY_PATH = mock(TreePath.class);
+  private static final DiagnosticPosition DUMMY_POSITION = mock();
+  private static final Fix DUMMY_FIX = mock();
+  private static final TreePath DUMMY_PATH = mock();
   private static final String DEFAULT_PACKAGE = "";
   private static final String CUSTOM_PACKAGE = "com.example";
   private static final String SIMPLE_CLASS_NAME = "MyRefasterRule";
@@ -149,7 +149,7 @@ final class AnnotatedCompositeCodeTransformerTest {
       ImmutableSet<? extends Annotation> annotations,
       Context expectedContext,
       Description returnedDescription) {
-    CodeTransformer codeTransformer = mock(CodeTransformer.class);
+    CodeTransformer codeTransformer = mock();
 
     when(codeTransformer.annotations()).thenReturn(indexAnnotations(annotations));
     doAnswer(
@@ -182,7 +182,7 @@ final class AnnotatedCompositeCodeTransformerTest {
   private static Context context() {
     // XXX: Use `ErrorProneOptions#processArgs` to test the
     // `AnnotatedCompositeCodeTransformer#overrideSeverity` logic.
-    Context context = mock(Context.class);
+    Context context = mock();
     when(context.get(ErrorProneOptions.class)).thenReturn(ErrorProneOptions.empty());
     return context;
   }

refaster-support/src/test/java/tech/picnic/errorprone/refaster/matchers/IsLambdaExpressionOrMethodReferenceTest.java

@@ -0,0 +1,72 @@
+package tech.picnic.errorprone.refaster.matchers;
+
+import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
+
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.CompilationTestHelper;
+import com.google.errorprone.bugpatterns.BugChecker;
+import org.junit.jupiter.api.Test;
+
+final class IsLambdaExpressionOrMethodReferenceTest {
+  @Test
+  void matches() {
+    CompilationTestHelper.newInstance(MatcherTestChecker.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import com.google.common.base.Predicates;",
+            "import java.util.function.Function;",
+            "import java.util.function.Predicate;",
+            "",
+            "class A {",
+            "  boolean negative1() {",
+            "    return true;",
+            "  }",
+            "",
+            "  String negative2() {",
+            "    return new String(new byte[0]);",
+            "  }",
+            "",
+            "  Predicate<String> negative3() {",
+            "    return Predicates.alwaysTrue();",
+            "  }",
+            "",
+            "  Predicate<String> positive1() {",
+            "    // BUG: Diagnostic contains:",
+            "    return str -> true;",
+            "  }",
+            "",
+            "  Predicate<String> positive2() {",
+            "    // BUG: Diagnostic contains:",
+            "    return str -> {",
+            "      return true;",
+            "    };",
+            "  }",
+            "",
+            "  Predicate<String> positive3() {",
+            "    // BUG: Diagnostic contains:",
+            "    return String::isEmpty;",
+            "  }",
+            "",
+            "  Function<byte[], String> positive4() {",
+            "    // BUG: Diagnostic contains:",
+            "    return String::new;",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  /** A {@link BugChecker} that simply delegates to {@link IsLambdaExpressionOrMethodReference}. */
+  @BugPattern(
+      summary = "Flags expressions matched by `IsLambdaExpressionOrMethodReference`",
+      severity = ERROR)
+  public static final class MatcherTestChecker extends AbstractMatcherTestChecker {
+    private static final long serialVersionUID = 1L;
+
+    // XXX: This is a false positive reported by Checkstyle. See
+    // https://github.com/checkstyle/checkstyle/issues/10161#issuecomment-1242732120.
+    @SuppressWarnings("RedundantModifier")
+    public MatcherTestChecker() {
+      super(new IsLambdaExpressionOrMethodReference());
+    }
+  }
+}

refaster-test-support/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.8.1-SNAPSHOT</version>
+        <version>0.9.0</version>
     </parent>
 
     <artifactId>refaster-test-support</artifactId>

run-mutation-tests.sh

@@ -16,6 +16,6 @@ targetTests=${1:-*}
 mvn clean test pitest:mutationCoverage \
   -DargLine.xmx=2048m \
   -Dverification.skip \
-  -DfailIfNoTests=false \
+  -Dsurefire.failIfNoSpecifiedTests=false \
   -Dtest="${targetTests}" \
   -DtargetTests="${targetTests}"